docs: change git fixes output to match the example "Fixes:" tag

The example "Fixes:" tag has the commit title in double quotes, whereas the suggested git fixes alias, a couple of lines below, also adds some outer parenthesis.

Although there doesn't appear to be a consistent format for the "Fixes:" tag, other than it should be a git commit sha followed by the commit title, the information in the docs should at least be consistent.

Signed-off-by: Frank Binns frank.binns@imgtec.com