core: minor refactor/reformat

+ Prefer cl-loop over cl-mapcan for performance reasons.
+ Remove unnecessary let form
+ Log doom-try-run-hook when doom-debug-mode is on.

core/core-dispatcher.el

@@ -57,7 +57,8 @@ omitted, show all available commands, their aliases and brief descriptions."
     (cl-destructuring-bind (command &key desc body)
         (let ((sym (intern (car args))))
           (or (assq sym doom--dispatch-command-alist)
-              (assq (cdr (assq sym doom--dispatch-alias-alist)) doom--dispatch-command-alist)
+              (assq (cdr (assq sym doom--dispatch-alias-alist))
+                    doom--dispatch-command-alist)
               (error "Invalid command: %s" (car args))))
       (if help
           (apply #'doom--dispatch-help command desc (cdr args))
@@ -71,7 +72,8 @@ bin/doom help.
 
 BODY will be run when this dispatcher is called."
   (declare (doc-string 3))
-  (cl-destructuring-bind (cmd &rest aliases) (doom-enlist command)
+  (cl-destructuring-bind (cmd &rest aliases)
+      (doom-enlist command)
     (macroexp-progn
      (append
       (when aliases

core/core-modules.el

@@ -94,8 +94,9 @@ Example:
       (unless (plist-member plist :path)
         (plist-put plist :path (or (plist-get old-plist :path)
                                    (doom-module-locate-path category module))))))
-  (let ((key (cons category module)))
-    (puthash key plist doom-modules)))
+  (puthash (cons category module)
+           plist
+           doom-modules))
 
 (defun doom-module-path (category module &optional file)
   "Like `expand-file-name', but expands FILE relative to CATEGORY (keywordp) and
@@ -205,11 +206,10 @@ non-nil, return paths of possible modules, activated or otherwise."
                        (remove-hook hook #',fn)))
                    (map-delete doom--deferred-packages-alist ',name)
                    (fmakunbound ',fn))))
-         (cl-mapcan (lambda (hook)
-                      (if (functionp hook)
-                          `((advice-add #',hook :before #',fn))
-                        `((add-hook ',hook #',fn))))
-                    hooks)
+         (cl-loop for hook in hooks
+                  collect (if (functionp hook)
+                              `(advice-add #',hook :before #',fn)
+                            `(add-hook ',hook #',fn)))
          `((map-put doom--deferred-packages-alist
                     ',name
                     '(,@hooks ,@(cdr (assq name doom--deferred-packages-alist)))))

core/core.el

@@ -245,6 +245,8 @@ original value of `symbol-file'."
 easier to tell where the came from.
 
 Meant to be used with `run-hook-wrapped'."
+  (when doom-debug-mode
+    (message "Running doom hook: %s" hook))
   (condition-case e
       (funcall hook)
     ((debug error)