Merge changes I8865dbf9,I42774ce8,I4192646d,Id7e08e57

* changes:
  Support searching changes that touch directories by regular expressions
  Allow matching changes with files that have no extension by 'ext' operator
  Support searching changes by directories
  Support searching changes by commit message footer

Documentation/user-search.txt

diff --git a/Documentation/user-search.txt b/Documentation/user-search.txt
index d596730..5d7a78b 100644
--- a/Documentation/user-search.txt
+++ b/Documentation/user-search.txt
@@ -276,6 +276,8 @@
 ones using a bracket expression). For example, to match all XML
 files named like 'name1.xml', 'name2.xml', and 'name3.xml' use
 `file:"^name[1-3].xml"`.
++
+Slash ('/') is used path separator.
 
 [[file]]
 file:'NAME', f:'NAME'::