Revert "Add c-or-c++-ts-mode (bug#59613)"

This reverts commit 1df2826639.

I forgot about the feature freeze, sorry :-)

etc/NEWS

@@ -3210,11 +3210,6 @@ programs in the C language.
 An optional major mode based on the tree-sitter library for editing
 programs in the C++ language.
 
-+++
-*** New command 'c-or-c++-ts-mode'.
-A command that automatically guesses the language of a header file,
-and enables either 'c-ts-mode' or 'c++-ts-mode' accordingly.
-
 +++
 *** New major mode 'java-ts-mode'.
 An optional major mode based on the tree-sitter library for editing

lisp/progmodes/c-ts-mode.el

@@ -858,50 +858,6 @@ This mode is independent from the classic cc-mode.el based
     (setq-local treesit-font-lock-settings (c-ts-mode--font-lock-settings 'cpp))
     (treesit-major-mode-setup)))
 
-;; We could alternatively use parsers, but if this works well, I don't
-;; see the need to change.  This is copied verbatim from cc-guess.el.
-(defconst c-ts-mode--c-or-c++-regexp
-  (eval-when-compile
-    (let ((id "[a-zA-Z_][a-zA-Z0-9_]*") (ws "[ \t]+") (ws-maybe "[ \t]*")
-          (headers '("string" "string_view" "iostream" "map" "unordered_map"
-                     "set" "unordered_set" "vector" "tuple")))
-      (concat "^" ws-maybe "\\(?:"
-              "using"     ws "\\(?:namespace" ws
-              "\\|" id "::"
-              "\\|" id ws-maybe "=\\)"
-              "\\|" "\\(?:inline" ws "\\)?namespace"
-              "\\(:?" ws "\\(?:" id "::\\)*" id "\\)?" ws-maybe "{"
-              "\\|" "class"     ws id
-              "\\(?:" ws "final" "\\)?" ws-maybe "[:{;\n]"
-              "\\|" "struct"     ws id "\\(?:" ws "final" ws-maybe "[:{\n]"
-              "\\|" ws-maybe ":\\)"
-              "\\|" "template"  ws-maybe "<.*?>"
-              "\\|" "#include"  ws-maybe "<" (regexp-opt headers) ">"
-              "\\)")))
-  "A regexp applied to C header files to check if they are really C++.")
-
-;;;###autoload
-(defun c-or-c++-ts-mode ()
-  "Analyze buffer and enable either C or C++ mode.
-
-Some people and projects use .h extension for C++ header files
-which is also the one used for C header files.  This makes
-matching on file name insufficient for detecting major mode that
-should be used.
-
-This function attempts to use file contents to determine whether
-the code is C or C++ and based on that chooses whether to enable
-`c-ts-mode' or `c++-ts-mode'."
-  (interactive)
-  (if (save-excursion
-        (save-restriction
-          (save-match-data ; Why `save-match-data'?
-            (widen)
-            (goto-char (point-min))
-            (re-search-forward c-ts-mode--c-or-c++-regexp nil t))))
-      (c++-ts-mode)
-    (c-ts-mode)))
-
 (provide 'c-ts-mode)
 
 ;;; c-ts-mode.el ends here