Highlight single character search results.

The logic behind the old code was that it was pointless to highlight
single characters, but it didn't explain why. This is useful for
searching for single character variable names, for instance.

Change-Id: Ic8cf60190c1a9caa1eb4441921e60f377fbee8d4
Reviewed-by: Eike Ziller <eike.ziller@digia.com>