Fix doc and code inconsistency: now use =verbatim= and ~code~.

* org.el (org-emphasis-alist): Use `org-verbatim' for =text=
and `org-code' for ~text~.

* org.texi (Emphasis and monospace): Document the use of
=verbatim= and ~code~ to be consistent with
`org-element-text-markup-successor'.

Thanks to Yasushi for reporting this.
Fix `org-open-at-point' on "docview"-type links

* lisp/org.el (org-open-at-point): Open "docview"-type links
  correctly, i.e., without adding "file+" first.
(org-open-file-with-system, org-open-file-with-emacs): Change
signature.  Deprecate functions.

* lisp/org-docview.el (org-docview-open): Open file even when no file
  number is specified.

This change removes "file+emacs" and "file+sys" types from
`org-link-protocols', since they are not hard-coded in
`org-open-at-point'.
Fix last commit

* lisp/org.el (org-link-types): Hardcode "file+emacs" and "file+sys".
ob-coq.el: Declare external functions
org-colview.el (org-columns-display-here): Let-bind `fm'

* org-colview.el (org-columns-display-here): Let-bind `fm'.
Merge branch 'maint'
org-element: Fix wrong cache behaviour

* lisp/org-element.el (org-element--cache-before-change): Correctly
  preserve match data.