💥 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.

modules/editor/file-templates/templates/rspec-mode/__

@@ -0,0 +1,3 @@
+# `(file-name-nondirectory buffer-file-name)`
+
+$0

modules/editor/file-templates/templates/rspec-mode/__.rspec

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+--color
+--require spec_helper
+--format=d

modules/editor/file-templates/templates/rspec-mode/__helper

@@ -0,0 +1,9 @@
+require 'bundler'
+
+$:.unshift File.expand_path('../lib', __FILE__)
+
+RSpec.configure do |c|
+  c.tty = true
+end
+
+$0