Use stressRule instead of stressrule for consistency

docs/voices.md

   - [dictionary](#dictionary)
   - [dictrules](#dictrules)
   - [replace](#replace)
+  - [stressRule](#stressrule)
   - [stressLength](#stresslength)
   - [stressAdd](#stressadd)
   - [stressAmp](#stressamp)
 The phoneme mnemonics can be defined for each language, but some are
 listed in [Phonemes](phonemes.md).
 
+### stressRule
+
+	stressRule <4 integer values>
+
+Four integer parameters. These correspond to:
+
+1. langopts->stress_rule (values in translate.h)
+2. langopts->stress_flags
+3. langopts->unstressed_wd1 (stress for $u word of 1 syllable)
+4. langopts->unstressed_wd2 (stress for $u word of >1 syllable) 
+
+If a value is not given, it defaults to zero. For example:
+"stressRule 2" is equal to "stressRule 2 0 0 0"
+
 ### stressLength
 
 	stressLength <8 integer values>

espeak-ng-data/lang/azc/nci

 language nci
 
 intonation 3
-stressrule 2
+stressRule 2
 stressLength  190  190  200  200  0  0  220  240

espeak-ng-data/lang/inc/ur

 maintainer Ejaz Shah <[email protected]>
 status testing
 
-stressrule 6
+stressRule 6
 

espeak-ng-data/lang/itc/la

 name Latin
 language la
-stressrule 2 33 0 2
+stressRule 2 33 0 2
 // rule=penultimate
 // flags=0100001 (no automatic secondary stress + don't stres monosyllables)
 // unstressed_wd1=0

src/libespeak-ng/voices.c

 	{ "intonation",   V_INTONATION },
 	{ "tunes",        V_TUNES },
 	{ "dictrules",    V_DICTRULES },
-	{ "stressrule",   V_STRESSRULE },
+	{ "stressRule",   V_STRESSRULE },
 	{ "stressopt",    V_STRESSOPT },
 	{ "replace",      V_REPLACE },
 	{ "words",        V_WORDGAP },