refactor!(cc): remove irony and rtags

BREAKING CHANGE: This removes the irony and rtags packages so we can
lean on LSP servers like clangd and ccls fully, which provide the same
features with much more consistency.

Close: #8049

modules/lang/cc/doctor.el

@@ -9,19 +9,6 @@
              (modulep! :tools tree-sitter))
          "This module requires (:tools tree-sitter)")
 
-(when (require 'rtags nil t)
-  ;; rtags
-  (when-let (bins (cl-remove-if #'rtags-executable-find
-                                (list rtags-rdm-binary-name
-                                      rtags-rc-binary-name)))
-    (warn! "Couldn't find the rtag client and/or server programs %s. Disabling rtags support"
-           bins)))
-
-;; irony server
-(when (require 'irony nil t)
-  (unless (file-directory-p irony-server-install-prefix)
-    (warn! "Irony server isn't installed. Run M-x irony-install-server")))
-
 (when (modulep! :completion company)
   ;; glslangValidator
   (unless (executable-find "glslangValidator")