refactor: deprecate featurep! for modulep!

featurep! will be renamed modulep! in the future, so it's been
deprecated. They have identical interfaces, and can be replaced without
issue.

featurep! was never quite the right name for this macro. It implied that
it had some connection to featurep, which it doesn't (only that it was
similar in purpose; still, Doom modules are not features). To undo such
implications and be consistent with its namespace (and since we're
heading into a storm of breaking changes with the v3 release anyway),
now was the best opportunity to begin the transition.

modules/lang/cc/config.el

@@ -17,7 +17,7 @@ This is ignored by ccls.")
   `((c-mode . nil)
     (c++-mode
      . ,(list "-std=c++1z" ; use C++17 draft by default
-              (when IS-MAC
+              (when (featurep :os 'macos)
                 ;; NOTE beware: you'll get abi-inconsistencies when passing
                 ;; std-objects to libraries linked with libstdc++ (e.g. if you
                 ;; use boost which wasn't compiled with libc++)
@@ -67,7 +67,7 @@ This is ignored by ccls.")
     :return "return"
     :yield "#require")
 
-  (when (featurep! +tree-sitter)
+  (when (modulep! +tree-sitter)
     (add-hook! '(c-mode-local-vars-hook
                  c++-mode-local-vars-hook)
                :append #'tree-sitter!))
@@ -125,7 +125,7 @@ This is ignored by ccls.")
 
 
 (use-package! irony
-  :unless (featurep! +lsp)
+  :unless (modulep! +lsp)
   :commands irony-install-server
   ;; Initialize compilation database, if present. Otherwise, fall back on
   ;; `+cc-default-compiler-options'.
@@ -146,11 +146,11 @@ This is ignored by ccls.")
     :hook (irony-mode . irony-eldoc))
 
   (use-package! flycheck-irony
-    :when (featurep! :checkers syntax)
+    :when (modulep! :checkers syntax)
     :config (flycheck-irony-setup))
 
   (use-package! company-irony
-    :when (featurep! :completion company)
+    :when (modulep! :completion company)
     :init (set-company-backend! 'irony-mode '(:separate company-irony-c-headers company-irony))
     :config (require 'company-irony-c-headers)))
 
@@ -166,7 +166,7 @@ This is ignored by ccls.")
 
 
 (use-package! company-cmake  ; for `cmake-mode'
-  :when (featurep! :completion company)
+  :when (modulep! :completion company)
   :after cmake-mode
   :config (set-company-backend! 'cmake-mode 'company-cmake))
 
@@ -176,7 +176,7 @@ This is ignored by ccls.")
 
 
 (use-package! company-glsl  ; for `glsl-mode'
-  :when (featurep! :completion company)
+  :when (modulep! :completion company)
   :after glsl-mode
   :config (set-company-backend! 'glsl-mode 'company-glsl))
 
@@ -185,7 +185,7 @@ This is ignored by ccls.")
 ;; Rtags Support
 
 (use-package! rtags
-  :unless (featurep! +lsp)
+  :unless (modulep! +lsp)
   ;; Only initialize rtags-mode if rtags and rdm are available.
   :hook ((c-mode-local-vars c++-mode-local-vars objc-mode-local-vars) . +cc-init-rtags-maybe-h)
   :preface (setq rtags-install-path (concat doom-etc-dir "rtags/"))
@@ -201,8 +201,8 @@ If rtags or rdm aren't available, fail silently instead of throwing a breaking e
         rtags-use-bookmarks nil
         rtags-completions-enabled nil
         rtags-display-result-backend
-        (cond ((featurep! :completion ivy)  'ivy)
-              ((featurep! :completion helm) 'helm)
+        (cond ((modulep! :completion ivy)  'ivy)
+              ((modulep! :completion helm) 'helm)
               ('default))
         ;; These executables are named rtags-* on debian
         rtags-rc-binary-name
@@ -235,7 +235,7 @@ If rtags or rdm aren't available, fail silently instead of throwing a breaking e
 ;;
 ;; LSP
 
-(when (featurep! +lsp)
+(when (modulep! +lsp)
   (add-hook! '(c-mode-local-vars-hook
                c++-mode-local-vars-hook
                objc-mode-local-vars-hook
@@ -261,7 +261,7 @@ If rtags or rdm aren't available, fail silently instead of throwing a breaking e
           :desc "References (Read)"     "r" #'+cc/ccls-show-references-read
           :desc "References (Write)"    "w" #'+cc/ccls-show-references-write)))
 
-  (when (featurep! :tools lsp +eglot)
+  (when (modulep! :tools lsp +eglot)
     ;; Map eglot specific helper
     (map! :localleader
           :after cc-mode
@@ -270,8 +270,7 @@ If rtags or rdm aren't available, fail silently instead of throwing a breaking e
 
     ;; NOTE : This setting is untested yet
     (after! eglot
-      ;; IS-MAC custom configuration
-      (when IS-MAC
+      (when (featurep :os 'macos)
         (add-to-list 'eglot-workspace-configuration
                      `((:ccls . ((:clang . ,(list :extraArgs ["-isystem/Library/Developer/CommandLineTools/usr/include/c++/v1"
                                                               "-isystem/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include"
@@ -279,8 +278,8 @@ If rtags or rdm aren't available, fail silently instead of throwing a breaking e
                                                   :resourceDir (cdr (doom-call-process "clang" "-print-resource-dir"))))))))))))
 
 (use-package! ccls
-  :when (featurep! +lsp)
-  :unless (featurep! :tools lsp +eglot)
+  :when (modulep! +lsp)
+  :unless (modulep! :tools lsp +eglot)
   :defer t
   :init
   (defvar ccls-sem-highlight-method 'font-lock)
@@ -298,11 +297,12 @@ If rtags or rdm aren't available, fail silently instead of throwing a breaking e
   (setq-hook! 'lsp-configure-hook
     ccls-sem-highlight-method (if lsp-enable-semantic-highlighting
                                   ccls-sem-highlight-method))
-  (when (or IS-MAC IS-LINUX)
+  (when (or (featurep :os 'macos)
+            (featurep :os 'linux))
     (setq ccls-initialization-options
           `(:index (:trackDependency 1
                     :threads ,(max 1 (/ (doom-system-cpus) 2))))))
-  (when IS-MAC
+  (when (featurep :os 'macos)
     (setq ccls-initialization-options
           (append ccls-initialization-options
                   `(:clang ,(list :extraArgs ["-isystem/Library/Developer/CommandLineTools/usr/include/c++/v1"