make comment-dwim in source code blocks more DWIM-ish
* lisp/org.el (org-insert-comment, org-comment-or-uncomment-region):
use the relevant language’s major mode comment function if called from
within a source block.
This patch makes it easier to (un)comment lines of babel source. Now
M-; in a soucre code block should Just Work.
The modification to ‘org-insert-comment’ also fixes a bug, whereby the
function would eat blank lines after it. The first block, where ! is
the point, would lead to the second instead of the third:
#+name: orig
#+begin_src org
xxxxxxx
!
yyyyyy
#+end_src
#+name: bad
#+begin_src org
xxxxxxx
#
yyyyyy
#+end_src
#+name: desired
#+begin_src org
xxxxxxx
#
yyyyyy
#+end_src
Also, the ‘org-comment-or-uncomment-region’ change results in an
undesirably move of the point after the comment is created. This is
because ‘comment-region’ wraps the call to ‘comment-region-function’
in a ‘save-excursion’. The org mode code deletes and reinserts the
whole babel block, which confuses save-excursion. Org carefully puts
the point back in the proper place, but comment-region’s
save-excursion then substitutes its own erroneous placement.