Replace the 'NOTE' and 'TODO' words with
the note and todo directives in the Compute API guide.
Improve some format in the guide.
e.g. Fix unnecessary bold characters.
Change-Id: I7e9d6b8a5228886fd5de03d12482481d2b652666
Closes-Bug: #1558459
In order to record the update history, use "git mv" to rename the
api-guide doc.
Depends-On: https://review.openstack.org/599276/
Part of bp support-to-query-nova-resources-filter-by-changes-before
Change-Id: I594dcead5edc222cb040cf11675fc76358e93ef8