Improved ChangeLog generation for vc log (Bug#16301)
* lisp/vc/diff-mode.el (diff-find-source-location): Fix docstring. * lisp/vc/add-log.el (change-log-unindented-file-names-re) (change-log-read-entries, change-log-read-defuns) (change-log-insert-entries): * lisp/vc/diff-mode.el (diff-add-log-current-defuns): * lisp/vc/log-edit.el (log-edit--insert-filled-defuns) (log-edit-fill-entry): New functions. (log-edit-mode): Set `log-edit-fill-entry' as `fill-paragraph-function'. (log-edit-generate-changelog-from-diff): New command. (log-edit-mode-map): Bind it to C-c C-w. * doc/emacs/maintaining.texi (Types of Log File, Log Buffer): * CONTRIBUTE: Document it. * etc/NEWS: Announce it. * test/lisp/vc/log-edit-tests.el (log-edit-fill-entry) (log-edit-fill-entry-joining): New tests.