Documention: web--browse: add info about "browser.<tool>.cmd" config var

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/config.txt

@@ -420,6 +420,11 @@ branch.<name>.rebase::
 	it unless you understand the implications (see linkgit:git-rebase[1]
 	for details).
 
+browser.<tool>.cmd::
+	Specify the command to invoke the specified browser. The
+	specified command is evaluated in shell with the URLs passed
+	as arguments. (See linkgit:git-web--browse[1].)
+
 browser.<tool>.path::
 	Override the path for the given tool that may be used to
 	browse HTML help (see '-w' option in linkgit:git-help[1]) or a

Documentation/git-web--browse.txt

@@ -27,6 +27,8 @@ The following browsers (or commands) are currently supported:
 * dillo
 * open (this is the default under Mac OS X GUI)
 
+Custom commands may also be specified.
+
 OPTIONS
 -------
 -b BROWSER|--browser=BROWSER::
@@ -43,16 +45,35 @@ OPTIONS
 CONFIGURATION VARIABLES
 -----------------------
 
+CONF.VAR (from -c option) and web.browser
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
 The web browser can be specified using a configuration variable passed
 with the -c (or --config) command line option, or the 'web.browser'
 configuration variable if the former is not used.
 
+browser.<tool>.path
+~~~~~~~~~~~~~~~~~~~
+
 You can explicitly provide a full path to your preferred browser by
 setting the configuration variable 'browser.<tool>.path'. For example,
 you can configure the absolute path to firefox by setting
 'browser.firefox.path'. Otherwise, 'git-web--browse' assumes the tool
 is available in PATH.
 
+browser.<tool>.cmd
+~~~~~~~~~~~~~~~~~~
+
+When the browser, specified by options or configuration variables, is
+not among the supported ones, then the corresponding
+'browser.<tool>.cmd' configuration variable will be looked up. If this
+variable exists then "git web--browse" will treat the specified tool
+as a custom command and will use a shell eval to run the command with
+the URLs passed as arguments.
+
+Note about git config --global
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
 Note that these configuration variables should probably be set using
 the '--global' flag, for example like this: