Remove subsumed repetitions in regexps

Make regexps smaller and faster by removing terms that are superfluous
by virtue of standing next to another term that matches more.  See
https://lists.gnu.org/archive/html/emacs-devel/2020-01/msg00949.html
for details.

* lisp/bs.el (bs--make-header-match-string):
* lisp/gnus/deuglify.el (gnus-outlook-repair-attribution-block):
* lisp/gnus/message.el (message-subject-trailing-was-ask-regexp)
(message-subject-trailing-was-regexp):
* lisp/informat.el (Info-validate):
* lisp/net/browse-url.el (browse-url-button-regexp):
* lisp/net/rcirc.el (rcirc-url-regexp):
* lisp/org/ob-core.el (org-babel-remove-result):
* lisp/org/ob-fortran.el (org-babel-fortran-ensure-main-wrap):
* lisp/org/org-capture.el (org-capture-set-target-location):
* lisp/org/org-table.el (org-table-expand-lhs-ranges):
* lisp/org/org.el (org-maybe-keyword-time-regexp, org-ts-regexp)
(org-ts-regexp-inactive, org-ts-regexp-both):
* lisp/play/gametree.el (gametree-hack-file-layout):
* lisp/progmodes/cc-mode.el (c-Java-defun-prompt-regexp):
* lisp/progmodes/idlw-shell.el (idlwave-shell-halting-error):
* lisp/progmodes/ruby-mode.el (ruby-mode-set-encoding):
* lisp/progmodes/verilog-mode.el (verilog-error-font-lock-keywords)
(verilog-verilint-off, verilog-case-indent-level)
(verilog-within-translate-off, verilog-start-translate-off)
(verilog-back-to-start-translate-off, verilog-end-translate-off)
(verilog-expand-dirnames):
* lisp/term.el (term-control-seq-regexp):
* lisp/textmodes/reftex-vars.el (featurep):
* lisp/url/url-gw.el (url-open-telnet):
* lisp/vc/ediff-ptch.el (ediff-context-diff-label-regexp):
* lisp/vc/pcvs-parse.el (cvs-parse-status):
* test/src/regex-emacs-tests.el (regex-tests-PCRE):
Remove subsumed repetitions.
* lisp/progmodes/sh-script.el (sh-syntax-propertize-function):
Simplify repetition of a repetition.

1 files changed, 6 insertions, 1 deletions

diff --git a/lisp/bs.el b/lisp/bs.el
index f5cb93b5169..337d22ecf83 100644
--- a/lisp/bs.el
+++ b/lisp/bs.el
@@ -173,7 +173,12 @@ return a string representing the column's value."
 
 (defun bs--make-header-match-string ()
   "Return a regexp matching the first line of a Buffer Selection Menu buffer."
-  (concat "^\\(" (mapconcat #'car bs-attributes-list " *") " *$\\)"))
+  (concat "^\\("
+          (apply #'concat (mapcan (lambda (e)
+                                    (and (not (equal (car e) ""))
+                                         (list " *" (car e))))
+                                  bs-attributes-list))
+          " *$\\)"))
 
 ;; Font-Lock-Settings
 (defvar bs-mode-font-lock-keywords