Check for absent pattern in menu_print_search_msg
Ignore empty pattern in file list search
Document that 'incsearch' affects local filter

Thanks to filterfalse.
Add docs for search_menu_list() function

And better prototype.
Fix segmentation fault on Alt-. in cmdline mode

What there since 0.7.7, broken on adding Ctrl-X shortcuts.
Fix result of search_menu_forwards()

It displayed message on the status bar, but returned 0.
Extract cmdline.c:search_submode_to_command_type()

Converts search command-line sub-mode to type of command for the
commands.c unit.
Consider search_menu_list result on CR for search
Repeat last search for empty pattern on search

Previous behaviour was strange, inconsistent with Vim and hard to
predict.
Merge branch 'fix-search-related-regressions'

* Fix segfault on empty menu search pattern.
* No message on empty file list search pattern.
* Document 'incsearch' and local filter relations.
* Fix segfault on Alt-.
* Fix menu search messages (I know, again).
* Repeat last search for empty pattern on search.