Backport commit af085ef40 from Emacs

* lisp/org-agenda.el (org-agenda-hide-tags-regexp)
(org-agenda-category-icon-alist):
* lisp/org-protocol.el (org-protocol-data-separator):
* lisp/org-table.el (org-table-number-regexp):
* lisp/ox-latex.el (org-latex-known-warnings):
Use 'regexp' instead of 'string' as type for values that are regexps
in defcustom declarations.

Use regexp type for regexps in defcustom declarations
af085ef40b961ca3466e8b2dfb7f722573e5a4cc
Mattias Engdegård
Thu Dec 26 16:50:58 2019 +0100

lisp/org-agenda.el

@@ -1906,7 +1906,7 @@ Nil means don't hide any tags."
   :group 'org-agenda-line-format
   :type '(choice
 	  (const  :tag "Hide none" nil)
-	  (string :tag "Regexp   ")))
+	  (regexp :tag "Regexp   ")))
 
 (defvaralias 'org-agenda-remove-tags-when-in-prefix
   'org-agenda-remove-tags)
@@ -2003,7 +2003,7 @@ category, you can use:
   (\"Emacs\" \\='(space . (:width (16))))"
   :group 'org-agenda-line-format
   :version "24.1"
-  :type '(alist :key-type (string :tag "Regexp matching category")
+  :type '(alist :key-type (regexp :tag "Regexp matching category")
 		:value-type (choice (list :tag "Icon"
 					  (string :tag "File or data")
 					  (symbol :tag "Type")

lisp/org-protocol.el

@@ -278,7 +278,7 @@ This should be a single regexp string."
   :group 'org-protocol
   :version "24.4"
   :package-version '(Org . "8.0")
-  :type 'string)
+  :type 'regexp)
 
 ;;; Helper functions:
 

lisp/org-table.el

@@ -206,7 +206,7 @@ Other options offered by the customize interface are more restrictive."
 		 "^\\([<>]?[-+^.0-9]*[0-9][-+^.0-9eEdDx()%]*\\|[<>]?[-+]?0[xX][[:xdigit:].]+\\|[<>]?[-+]?[0-9]+#[0-9a-zA-Z.]+\\|nan\\|[-+u]?inf\\)$")
 	  (const :tag "Very General Number-Like, including hex and Calc radix, allows comma as decimal mark"
 		 "^\\([<>]?[-+^.,0-9]*[0-9][-+^.0-9eEdDx()%]*\\|[<>]?[-+]?0[xX][[:xdigit:].]+\\|[<>]?[-+]?[0-9]+#[0-9a-zA-Z.]+\\|nan\\|[-+u]?inf\\)$")
-	  (string :tag "Regexp:")))
+	  (regexp :tag "Regexp:")))
 
 (defcustom org-table-number-fraction 0.5
   "Fraction of numbers in a column required to make the column align right.

lisp/ox-latex.el

@@ -1241,7 +1241,7 @@ calling `org-latex-compile'."
   :package-version '(Org . "8.3")
   :type '(repeat
 	  (cons
-	   (string :tag "Regexp")
+	   (regexp :tag "Regexp")
 	   (string :tag "Message"))))