! exclamation (important)

You can mark up “main” index entries by prefixing them with an exclamation mark. The references to “main” entries are emphasized in the generated index. For example, if two pages contain

   .. index:: Python

and one page contains ::

   .. index:: ! Python

then the backlink to the latter page is emphasized among the three backlinks.

For index directives containing only "single" entries, there is a shorthand
notation::

   .. index:: BNF, grammar, syntax, notation

This creates four index entries.

.. versionchanged:: 1.1
   Added ``see`` and ``seealso`` types, as well as marking main entries.