ru: fix лёгких, мягкий, etc.

Revert "ru: 'х' made less stressed"

This reverts commit 33c9e800a3.

This commit made the [x] phoneme not audible, and made it act like
a glottal stop in words like мягкий.

phsource/ph_russian

@@ -26,7 +26,7 @@ phoneme x
   lengthmod 3
   Vowelin f1=0  f2=2300 200 400  f3=-100 80
   Vowelout f1=0 f2=2300 300 400  f3=-100 80  rms=20
-  WAV(ufric/x_hr, 5)
+  WAV(ufric/x_hr, 30)
 endphoneme