Remove vestigial mentions of the :feature category

It was removed long, long ago.

modules/app/twitter/autoload.el

@@ -6,7 +6,7 @@
 ;;;###autoload
 (defun +twitter-display-buffer-fn (buf)
   "A replacement display-buffer command for `twittering-pop-to-buffer-function'
-that works with the feature/popup module."
+that works with the ui/popup module."
   (let ((win (selected-window)))
     (display-buffer buf)
     ;; This is required because the new window generated by `pop-to-buffer'

modules/editor/evil/README.org

@@ -1,4 +1,4 @@
-#+TITLE:   feature/evil
+#+TITLE:   editor/evil
 #+DATE:    February 2, 2017
 #+SINCE:   v2.0
 #+STARTUP: inlineimages nofold

modules/ui/workspaces/autoload/workspaces.el

@@ -1,4 +1,4 @@
-;;; feature/workspaces/autoload/workspaces.el -*- lexical-binding: t; -*-
+;;; ui/workspaces/autoload/workspaces.el -*- lexical-binding: t; -*-
 
 (defvar +workspace--last nil)
 (defvar +workspace--index 0)