Output warning about not highlighted block through Sphinx' warn()

Sphinx' warn() function stores information about position of processing
code, so now error message contains exact position of error.
Fix highlighting for P4 stuff, config files, logs, IRC commands, exceptions

Hightlighted as "none".
Fix highlighting for command line examples

Highlight as "bash".
Fix highlighting of notes

Note that there is one new TODO about missing code example.
Fix IRC logs highlighting

Highlight as "irc".