Adjust previous electric.el and elec-pair.el change

This fixes a serious bug introduced previously
electric-pair-inhibit-if-helps-balance and
electric-pair-skip-if-helps-balance, whereby "innocent" markers were
being pushed by those function's new save-change-and-restore
semantics.  The fix can probably still be improved.

It also adds comments to parts of the code, where deemed necessary.

* lisp/elec-pair.el (electric-pair--insert): Add comment.
(electric-pair--save-literal-point-excursion): New helper macro.
(electric-pair-inhibit-if-helps-balance)
(electric-pair-skip-if-helps-balance): Don't use
insert-before-markers since it may hurt other markers that have
nothing to do with the 'save-excursion'.
(electric-pair-post-self-insert-function): Use
electric-pair--save-literal-point-excursion.

* lisp/electric.el (electric-indent-post-self-insert-function):
Remove lexical variable.

1 files changed, 4 insertions, 6 deletions

diff --git a/lisp/electric.el b/lisp/electric.el
index b9458776e3b..657913a3961 100644
--- a/lisp/electric.el
+++ b/lisp/electric.el
@@ -270,14 +270,12 @@ or comment."
         ;; hence copied).
         (let ((at-newline (<= pos (line-beginning-position))))
           (when at-newline
-            (let ((before (copy-marker (1- pos) t))
-                  inhibit-reindentation)
+            (let ((before (copy-marker (1- pos) t)))
               (save-excursion
                 (unless
-                    (setq inhibit-reindentation
-                          (or (memq indent-line-function
-                                    electric-indent-functions-without-reindent)
-                              electric-indent-inhibit))
+                    (or (memq indent-line-function
+                              electric-indent-functions-without-reindent)
+                        electric-indent-inhibit)
                   ;; Don't reindent the previous line if the
                   ;; indentation function is not a real one.
                   (goto-char before)