[1.2.X] Fixed #14767 -- Reflowed paragraphs and cleaned up some markup/links...

[1.2.X] Fixed #14767 -- Reflowed paragraphs and cleaned up some markup/links in the topics/db/optimizations docs. Thanks to adamv for the report and patch.

Backport of [14690] from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.2.X@14691 bcc190cf-cafb-0310-a4f2-bffc1f526a37