Velarize [n] to [ŋ] before velar stops in Elvish

I’m not aware of any statement by Tolkien to this effect, but it just
seems natural to me, and the [ŋ] is at least found in the Omikhleia
Sindarin dictionary [1] (e.g. entry tinc, [tˈiŋk]).

Based on a similar phoneme rule in ph_english.

[1]: https://www.jrrvf.com/hisweloke/sindar/index.html

phsource/ph_quenya

@@ -1,3 +1,11 @@
+phoneme n
+  IF nextPhW(isVelar) THEN // /n/ is velarized to /N/ when before velar stops
+    ChangePhoneme(N)
+  ENDIF
+  CALL base1/n
+endphoneme
+
+
 phoneme ui
   vwl starttype #u endtype #i
   length 270

phsource/ph_sindarin

@@ -1,3 +1,11 @@
+phoneme n
+  IF nextPhW(isVelar) THEN // /n/ is velarized to /N/ when before velar stops
+    ChangePhoneme(N)
+  ENDIF
+  CALL base1/n
+endphoneme
+
+
 phoneme aE
   vwl starttype #a endtype #e
   length 270