💥 Remove :feature category

:feature was a "catch-all" category. Many of its modules fit better in
other categories, so they've been moved:

- feature/debugger -> tools/debugger
- feature/evil -> editor/evil
- feature/eval -> tools/eval
- feature/lookup -> tools/lookup
- feature/snippets -> editor/snippets
- feature/file-templates -> editor/file-templates
- feature/workspaces -> ui/workspaces

More potential changes in the future:

- A new :term category for terminal emulation modules (eshell, term and
  vterm).
- A new :os category for modules dedicated to os-specific functionality.
  The :tools macos module would fit here, but so would modules for nixos
  and arch.
- A new :services category for web-service integration, like wakatime,
  twitter, elfeed, gist and pastebin services.

init.example.el

@@ -8,17 +8,7 @@
 ;; More information about these modules (and what flags they support) can be
 ;; found in modules/README.org.
 
-(doom! :feature
-       ;;debugger          ; FIXME stepping through code, to help you add bugs
-       eval              ; run code, run (also, repls)
-       (evil +everywhere); come to the dark side, we have cookies
-       file-templates    ; auto-snippets for empty files
-       (lookup           ; helps you navigate your code and documentation
-        +docsets)        ; ...or in Dash docsets locally
-       snippets          ; my elves. They type so I don't have to
-       workspaces        ; tab emulation, persistence & separate workspaces
-
-       :completion
+(doom! :completion
        company           ; the ultimate code completion backend
        ;;helm              ; the *other* search engine for love and life
        ;;ido               ; the other *other* search engine...
@@ -46,14 +36,18 @@
        vc-gutter         ; vcs diff in the fringe
        vi-tilde-fringe   ; fringe tildes to mark beyond EOB
        window-select     ; visually switch windows
+       workspaces        ; tab emulation, persistence & separate workspaces
 
        :editor
+       (evil +everywhere); come to the dark side, we have cookies
+       file-templates    ; auto-snippets for empty files
        fold              ; (nigh) universal code folding
        ;;(format +onsave)  ; automated prettiness
        ;;lispy             ; vim for lisp, for people who dont like vim
        multiple-cursors  ; editing in many places at once
        ;;parinfer          ; turn lisp into python, sort of
        rotate-text       ; cycle region at point between text candidates
+       snippets          ; my elves. They type so I don't have to
 
        :emacs
        (dired            ; making dired pretty [functional]
@@ -68,13 +62,17 @@
 
        :tools
        ;;ansible
+       ;;debugger          ; FIXME stepping through code, to help you add bugs
        ;;direnv
        ;;docker
        ;;editorconfig      ; let someone else argue about tabs vs spaces
        ;;ein               ; tame Jupyter notebooks with emacs
+       eval              ; run code, run (also, repls)
        flycheck          ; tasing you for every semicolon you forget
        ;;flyspell          ; tasing you for misspelling mispelling
        ;;gist              ; interacting with github gists
+       (lookup           ; helps you navigate your code and documentation
+        +docsets)        ; ...or in Dash docsets locally
        ;;lsp
        ;;macos             ; MacOS-specific commands
        magit             ; a git porcelain for Emacs