git-gui: Bind M1-P to push action

Users often need to be able to push the current branch so that they
can publish their recent changes to anyone they are collaborating
with on the project.  Associating a keyboard action with this will
make it easier for keyboard-oriented users to quickly activate the
push features.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
diff --git a/git-gui.sh b/git-gui.sh
index a1cf873..c22a431 100755
--- a/git-gui.sh
+++ b/git-gui.sh
@@ -1525,7 +1525,8 @@
 
 	menu .mbar.push
 	.mbar.push add command -label {Push...} \
-		-command do_push_anywhere
+		-command do_push_anywhere \
+		-accelerator $M1T-P
 }
 
 if {[is_MacOSX]} {
@@ -2148,6 +2149,10 @@
 	bind . <$M1B-Key-n> do_create_branch
 	bind . <$M1B-Key-N> do_create_branch
 }
+if {[is_enabled transport]} {
+	bind . <$M1B-Key-p> do_push_anywhere
+	bind . <$M1B-Key-P> do_push_anywhere
+}
 
 bind .   <Key-F5>     do_rescan
 bind .   <$M1B-Key-r> do_rescan