en: don't velarize n across word boundaries

It is possible -- especially at higher speeds -- for the n at the
end of a word to be velarised if the next word starts with a velar
plosive. I prefer the velarised sound between word boundaries, but
others do not. As such, limit the velarisation to within the word
only.

[1]	https://en.wikipedia.org/wiki/English_phonology

phsource/ph_english

@@ -111,7 +111,7 @@ endphoneme
 phoneme n
   vcd alv nas
   ipa n
-  IF nextPh(isVelar) THEN // /n/ is velarized to /N/ when before velar stops
+  IF nextPhW(isVelar) THEN // /n/ is velarized to /N/ when before velar stops
     ChangePhoneme(N)
   ENDIF
   CALL base1/n