docs/add_language.md style and other fixes

docs/add_language.md

 # Adding or Improving a Language
 
-# Table of contents
-
 - [Language Code](#language-code)
 - [Language Files](#language-files)
 - [Voice File](#voice-file)
 - [Phoneme Definition File](#phoneme-definition-file)
 - [Dictionary Files](#dictionary-files)
 - [Program Code](#program-code)
-- [Compiling rules file for debugging](#compiling-rules-file-for-debugging)
+- [Compiling Rules File for Debugging](#compiling-rules-file-for-debugging)
 - [Improving a Language](#improving-a-language)
 
 ----------
 during testing because most of the options can also be set in the voice
 file in espeak-data/voices (see [Voice Files](voices.md)).
 
-## Compiling rules file for debugging
+## Compiling Rules File for Debugging
 
 When `espeak-ng` is invoked with `-X` parameter, it shows more detailed trace of 
 chosen language rules for pronunciation. This trace can show line numbers also, 
 
 To do this, go to `espeak-ng` project root folder, then:
 
-    cd dictsource/
-    ../src/espeak-ng --compile-debug=en
+	cd dictsource
+	../src/espeak-ng --compile-debug=en
 
 When invoked in following way:
 
-    es -ven -X "Test."
+	espeak-ng -ven -X "Test."
 
 It will show:
 
-```
---------------
-Translate 'test'
-  1  5965:  t [t]
-
-  1  2104:  e [E]
-
-  1  5725:  s [s]
-
-  1  5965:  t [t]
-
- t'Est
-```
+	Translate 'test'
+	  1  5965:  t [t]
+	
+	  1  2104:  e [E]
+	
+	  1  5725:  s [s]
+	
+	  1  5965:  t [t]
+	
+	 t'Est
 
 ## Improving a Language