godoc: fix identifier search
godoc: fix identifier search

Thanks to Andrey Mirtchovski for tracking this down.

This was broken by CL 5528077 which removed the InsertSemis
flag from go/scanner - as a result, semicolons are now always
inserted and the respective indexer code checked for the
wrong token.

Replaced the code by a direct identifier test.

R=rsc
CC=golang-dev
http://codereview.appspot.com/5606065

tav/go,tav/go,tav/go,tav/go,tav/go,tav/go,tav/go