Fix API output formatting (change lines delimited with * as bold)

Problem: on API documentation pages, lines delimited with asterisks
are automatically converted to bold. However, some lines aren't,
such as the one with the url in the main header of the root API page:
https://en.wikipedia.org/w/api.php

Not only this is breaks the standard formatting for module headers, etc,
but if the font used by the browser for monospaced text
doesn't preserve character width between bold and regular weight
(which it should), any layout structures will break.
Example: http://i.imgur.com/PVh6i.png

The regex that applies bold to the lines starting and ending in *
doesn't accept < and > inside the string,
but these are added by the url-formatting regex.
Simply changing the order of these operations fixes the issue.

Note: this change also removes the regex applying italics
      to lines in the $ ... $ form, as suggested by Anomie and Yurik
      in code review comments.

Change-Id: I7173f812bebb8a722fefdaa6cce9fcd554c82c84