Rationalize `org-link-(un)escape'

* contrib/lisp/org-contacts.el (org-contacts-vcard-format):
* contrib/lisp/org-link-edit.el (org-link-edit--link-data):
* contrib/lisp/org-notmuch.el (org-notmuch-search-store-link):
(org-notmuch-search-follow-link):
(org-notmuch-tree-follow-link):
* lisp/org-docview.el (org-docview-export):
* lisp/org-element.el (org-element-link-parser):
* lisp/org-lint.el (org-lint-link-to-local-file):
* lisp/org-protocol.el (org-protocol-split-data):
(org-protocol-parse-parameters):
* lisp/org.el (org-open-at-point):
(org-display-inline-images):
* lisp/ox-ascii.el (org-ascii-link):
* lisp/ox-html.el (org-html-link):
* lisp/ox-latex.el (org-latex--inline-image):
(org-latex-link):
* lisp/ox-publish.el (org-publish-resolve-external-link):
* lisp/ox.el (org-export-custom-protocol-maybe):
(org-export-resolve-fuzzy-link): Do not call `org-link-unescape' when
the link is obtained through the parser or as a user input.
* doc/org-manual.org (Link Format): Document escape syntax.

See <http://lists.gnu.org/r/emacs-orgmode/2019-02/msg00320.html>

org-contacts.el

@@ -1013,7 +1013,7 @@ to do our best."
 			(setq phones-list (org-contacts-remove-ignored-property-values ignore-list (org-contacts-split-property tel)))
 			(setq result "")
 			(while phones-list
-			  (setq result (concat result  "TEL:" (org-link-unescape (org-contacts-strip-link (car phones-list))) "\n"))
+			  (setq result (concat result  "TEL:" (org-contacts-strip-link (org-link-unescape (car phones-list))) "\n"))
 			  (setq phones-list (cdr phones-list)))
 			result))
 	    (when bday