docs: restructure voices.md to avoid an extra level in the ToC structure.

docs/voices.md

 # Voice Files
 
-- [Contents of Voice Files](#contents-of-voice-files)
-  - [Identification Attributes](#identification-attributes)
-    - [name](#name)
-    - [language](#language)
-    - [gender](#gender)
-  - [Voice Attributes](#voice-attributes)
-    - [pitch](#pitch)
-    - [formant](#formant)
-    - [freq\_add](#freq_add)
-    - [echo](#echo)
-    - [tone](#tone)
-    - [flutter](#flutter)
-    - [roughness](#roughness)
-    - [voicing](#voicing)
-    - [consonants](#consonants)
-    - [breath](#breath)
-    - [breathw](#breathw)
-    - [speed](#speed)
-    - [words](#words)
-  - [Language Attributes](#language-attributes)
-    - [phonemes](#phonemes)
-    - [dictionary](#dictionary)
-    - [dictrules](#dictrules)
-    - [replace](#replace)
-    - [stressLength](#stressLength)
-    - [stressAdd](#stressAdd)
-    - [stressAmp](#stressAmp)
-    - [intonation](#intonation)
-    - [charset](#charset)
-    - [dictmin](#dictmin)
-    - [alphabet2](#alphabet2)
-    - [dictdialect](#dictdialect)
+- [Identification Attributes](#identification-attributes)
+  - [name](#name)
+  - [language](#language)
+  - [gender](#gender)
+- [Voice Attributes](#voice-attributes)
+  - [pitch](#pitch)
+  - [formant](#formant)
+  - [freq\_add](#freq_add)
+  - [echo](#echo)
+  - [tone](#tone)
+  - [flutter](#flutter)
+  - [roughness](#roughness)
+  - [voicing](#voicing)
+  - [consonants](#consonants)
+  - [breath](#breath)
+  - [breathw](#breathw)
+  - [speed](#speed)
+  - [words](#words)
+- [Language Attributes](#language-attributes)
+  - [phonemes](#phonemes)
+  - [dictionary](#dictionary)
+  - [dictrules](#dictrules)
+  - [replace](#replace)
+  - [stressLength](#stressLength)
+  - [stressAdd](#stressAdd)
+  - [stressAmp](#stressAmp)
+  - [intonation](#intonation)
+  - [charset](#charset)
+  - [dictmin](#dictmin)
+  - [alphabet2](#alphabet2)
+  - [dictdialect](#dictdialect)
 
 ----------
 
 can copy your preferred voice to "default" so you can use the speak command
 without the need to specify a voice.
 
-## Contents of Voice Files
+## Identification Attributes
 
-The `language` attribute is mandatory. All the other attributes are
-optional.
-
-### Identification Attributes
-
-#### name
+### name
 
 	name <name>
 
 A name given to this voice.
 
-#### language
+### language
 
 	language <language code> [<priority>]
 
-This attribute should appear before the other attributes which are
-listed below.
+__NOTE:__ This attribute is mandatory and should appear before the other
+attributes which are listed below.
 
 It selects the default behaviour and characteristics for the language,
 and sets default values for "phonemes", "dictionary" and other
 the second `language` line, it would be disfavoured for "en" for being
 a more specialised voice.
 
-#### gender
+### gender
 
 	gender <gender> [<age>]
 
 *  \<gender\> may be male, female, or unknown.  
 *  \<age\> is optional and gives an age in years.
 
-### Voice Attributes
+## Voice Attributes
 
-#### pitch
+### pitch
 
 	pitch <base> <range>
 
 Hz) The second controls the range of pitches used by the voice. Setting
 it equal to the base pitch will give a monotone. The default values are 82 118.  
 
-#### formant
+### formant
 
 	formant <number> <frequency> <strength> <width> <freq_add>
 
 resonance peaks of the voice. Values are percentages of the default
 values. Changing these affects the tone/quality of the voice.
 
-#### freq\_add
+### freq\_add
 
 Adds a constant value (in Hz) to the frequency of the formant peak. The value
 may be negative.
 * Formants 6,7,8 are weak, high frequency, additions to vowels to give a
   clearer sound.
 
-#### echo
+### echo
 
 	echo <delay> <amplitude>
 
 listening through a domestic stereo sound system, rather than small computer
 speakers.
 
-#### tone
+### tone
 
 Controls the tone of the sound.  
 
 This `tone` statement can also appear in `espeak-data/config`, in which case
 it applies to all voices which don't have their own `tone` statement.
 
-#### flutter
+### flutter
 
 	flutter <value>
 
 Adds pitch fluctuations to give a wavering or older-sounding voice. A
 large value (eg. 20) makes the voice sound "croaky".
 
-#### roughness
+### roughness
 
 	roughness <value>
 
 Reduces the amplitude of alternate waveform cycles in order to make the
 voice sound creaky.
 
-#### voicing
+### voicing
 
 	voicing <value>
 
 Adjusts the strength of formant-synthesized sounds (vowels and sonorant
 consonants).
 
-#### consonants
+### consonants
 
 	consonants <value> <value>
 
 The second value is the strength of the noise component of voiced
 consonants such as "z" and "d".
 
-#### breath
+### breath
 
 	breath <up to 8 integer values>
 
 	flutter  20
 	formant   0 100 0 100   // remove formant 0 
 
-#### breathw
+### breathw
 
 	breathw <up to 8 integer values>
 
 attribute. If `breathw` values are not given, then suitable default
 values will be used.
 
-#### speed
+### speed
 
 	speed <value>
 
 can be used if a language voice seems faster or slower compared to other
 voices.
 
-#### words
+### words
 
 	words <integer value> <integer value>
 
 will put a short pause between two words where the first word end with a
 vowel and the next start with a vowel.
 
-### Language Attributes
+## Language Attributes
 
-#### phonemes
+### phonemes
 
 	phonemes <name>
 
 of the same language can use different phoneme sets, to give different
 accents.
 
-#### dictionary
+### dictionary
 
 	dictionary <name>
 
 phonemes. This parameter is usually not needed as it is set by default
 to the first two letters of "language" parameter.
 
-#### dictrules
+### dictrules
 
 	dictrules <list of rule numbers>
 
 dictionary file and also its `*_list` exceptions list. See
 [Text to Phoneme Translation](dictionary.md).
 
-#### replace
+### replace
 
 	replace <flags> <phoneme> <replacement phoneme>
 
 The phoneme mnemonics can be defined for each language, but some are
 listed in [Phonemes](phonemes.md).
 
-#### stressLength
+### stressLength
 
 	stressLength <8 integer values>
 
 * 6 stressed syllable (the main syllable in stressed words)
 * 7 tonic syllable (by default, the last stressed syllable in the clause) 
 
-#### stressAdd
+### stressAdd
 
 	stressAdd <8 integer values>
 
 `stressLength` values. They are used in the voice variant files in
 `espeak-data/voices/!v` to give some variety. Negative values may be used.
 
-#### stressAmp
+### stressAmp
 
 	stressAmp <8 integer values>
 
 The general default values are: 16, 16, 20, 20, 20, 24, 24, 22, although
 these defaults may be different for particular languages.
 
-#### intonation
+### intonation
 
 	intonation <param1>
 
 * 3 -- Less intonation, and comma does not raise the pitch.  
 * 4 -- Pitch rises (rather than falls) at the end of sentence.
 
-#### charset
+### charset
 
 	charset <param1>
 
 The ISO 8859 character set number. (not all are implemented).
 
-#### dictmin
+### dictmin
 
 	dictmin <value>
 
 (the file `espeak-data/*_dict`) is less than this size then a
 warning is given.
 
-#### alphabet2
+### alphabet2
 
 	alphabet2 <alphabet> <language>
 
 Alphabets names include: latin, cyr (cyrillic), ar (arabic). The default
 language for latin alphabet is English.
 
-#### dictdialect
+### dictdialect
 
 	dictdialect <dialect>