Documentation: config: add "browser.<tool>.path".

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

Documentation/config.txt

@@ -367,6 +367,10 @@ branch.<name>.rebase::
 	it unless you understand the implications (see linkgit:git-rebase[1]
 	for details).
 
+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].
+
 clean.requireForce::
 	A boolean to make git-clean do nothing unless given -f
 	or -n.   Defaults to true.