language: remove "may change" notice
language: remove "may change" notice

Package should be pretty stable now.
No backwards incompatible changes expected after the currently
deprecated functionality has been removed.

Change-Id: I02e91082a9d90c0ed527d67ba00b36226dfe265e
Reviewed-on: https://go-review.googlesource.com/16869
Reviewed-by: Hyang-Ah Hana Kim <d7e82c3c07f92613bcbf9a1e88f6b96c13caa3b0@gmail.com>

cmars/tools,golang/text,cmars/tools,cmars/tools,cmars/tools