Corrected some typos in the documentation: occured -> occurred. its ->

Corrected some typos in the documentation: occured -> occurred. its ->

2008-01-16  Murray Cumming  <murrayc@murrayc.com>

* gappinfo.c:
* gdatainputstream.c:
* gfile.c:
* gfileoutputstream.c:
* ginputstream.c:
* gmount.c:
* goutputstream.c:
* gseekable.c:
* gunixmounts.c: Corrected some typos in the documentation:
occured -> occurred.
its -> it's (where appropriate).

svn path=/trunk/; revision=6322