Add new command prelude-top-join-line

Saner version of the built-in `join-line`, that joins lines from the top
to the bottom.

core/prelude-core.el

@@ -97,6 +97,11 @@ Position the cursor at its beginning, according to the current mode."
   (move-end-of-line nil)
   (newline-and-indent))
 
+(defun prelude-top-join-line ()
+  "Join the current line with the line beneath it."
+  (interactive)
+  (delete-indentation 1))
+
 (defun prelude-move-line-up ()
   "Move the current line up."
   (interactive)

core/prelude-global-keybindings.el

@@ -45,7 +45,7 @@
                                 (other-window -1))) ;; back one
 
 ;; Indentation help
-(global-set-key (kbd "C-x ^") 'join-line)
+(global-set-key (kbd "M-^") 'prelude-top-join-line)
 
 ;; Start proced in a similar manner to dired
 (global-set-key (kbd "C-x p") 'proced)