Add binding for invoking git diff from fish

With alt-d

Install/Templates/config/fish/functions/fish_user_key_bindings.fish

@@ -1,3 +1,4 @@
 function fish_user_key_bindings --description 'My custom key bindings'
 	bind \eg git_status_short
+	bind \ed git_diff
 end

Install/Templates/config/fish/functions/git_diff.fish

@@ -0,0 +1,6 @@
+function git_diff --description 'Git diff encapsulation for key binding'
+	echo
+	git diff
+	echo \n
+	commandline -f repaint
+end