git diff: hunk header config

[Michael Brand <michael.ch.brand@gmail.com>]

Hi all

I suggest to change the config of git diff in the org-mode.git repo to
the more helpful hunk header (the @@...@@ line) style:

#+begin_src diff
@@ -12991,7 +12991,7 @@ (defun org-align-tags-here (to-col)
          (goto-char (match-beginning 1))
          (insert " ")
          (delete-region (point) (1+ (match-beginning 2)))
-         (setq ncol (max (1+ (current-column))
+         (setq ncol (max (current-column)
                          (1+ col)
                          (if (> to-col 0)
                              to-col
#+end_src

which is similar to GNU diff -p/--show-c-function. The current, not
configured default "style" is:

#+begin_src diff
@@ -12991,7 +12991,7 @@ If ONOFF is `on' or `off', don't toggle but set to thi
          (goto-char (match-beginning 1))
          (insert " ")
          (delete-region (point) (1+ (match-beginning 2)))
-         (setq ncol (max (1+ (current-column))
+         (setq ncol (max (current-column)
                          (1+ col)
                          (if (> to-col 0)
                              to-col
#+end_src

Would that be commonly welcome for at least firstly Emacs Lisp and texinfo?

If yes, the following is to be added to the org-mode.git repo:

1) new file .gitattributes:
#+begin_src
*.el    diff=el
*.texi  diff=texinfo
#+end_src

2) append to .git/config:
#+begin_src
[diff "el"]
	xfuncname = "^(\\(def[a-z]+ .+)$"
[diff "texinfo"]
	xfuncname="^(@(sub)*section.*)$"
#+end_src

I hope that somebody can do this in the repo in such a way that it
will be effective after git pull and git clone automatically, so that
nobody has to care about later.

Michael