2019-12-05 regexp lint fixes

2019-12-05 regexp lint fixes

* lisp/org/org-agenda.el (org-agenda-filter):
Fix unescaped literal ‘+’ in regexp.  Reported by Mattias Engdegård in:
https://lists.gnu.org/r/emacs-devel/2019-12/msg00215.html
* lisp/org/org.el (org-clone-subtree-with-time-shift):
Fix a regexp typo that mishandled strings like ‘\1d’,
reported by the same emaikl.
* lisp/progmodes/verilog-mode.el (verilog-inject-inst):
Omit unnecessary ‘?’ in regexp.  Reported by Mattias Engdegård in:
https://lists.gnu.org/r/emacs-devel/2019-12/msg00217.html