Major optimization refactor, across the board

+ enable lexical-scope everywhere (lexical-binding = t): ~5-10% faster
  startup; ~5-20% general boost
+ reduce consing, function calls & garbage collection by preferring
  cl-loop & dolist over lambda closures (for mapc[ar], add-hook, and
  various cl-lib filter/map/reduce functions) -- where possible
+ prefer functions with dedicated opcodes, like assq (see byte-defop's
  in bytecomp.el for more)
+ prefer pcase & cond (faster) over cl-case
+ general refactor for code readability
+ ensure naming & style conventions are adhered to
+ appease byte-compiler by marking unused variables with underscore
+ defer minor mode activation to after-init, emacs-startup or
  window-setup hooks; a customization opportunity for users + ensures
  custom functionality won't interfere with startup.

modules/app/rss/autoload.el

@@ -1,4 +1,4 @@
-;;; app/rss/autoload.el
+;;; app/rss/autoload.el -*- lexical-binding: t; -*-
 
 ;;;###autoload
 (defun =rss ()

modules/app/rss/config.el

@@ -1,4 +1,4 @@
-;;; app/rss/config.el
+;;; app/rss/config.el -*- lexical-binding: t; -*-
 
 ;; This is an opinionated workflow that turns Emacs into an RSS reader, inspired
 ;; by apps Reeder and Readkit. It can be invoked via `=rss'. Otherwise, if you
@@ -31,8 +31,8 @@
   (make-directory elfeed-db-directory t)
 
   ;; Ensure elfeed buffers are treated as real
-  (push (lambda (buf) (string-match-p "^\\*elfeed" (buffer-name buf)))
-        doom-real-buffer-functions)
+  (cl-pushnew (lambda (buf) (string-match-p "^\\*elfeed" (buffer-name buf)))
+              doom-real-buffer-functions)
 
   ;; Enhance readability of a post
   (add-hook 'elfeed-show-mode-hook #'+rss|elfeed-wrap)