lang/ruby: major refactor

+ Robe is now to be started manually.
+ Adds more keybindings for robe (including <localleader> ' for
  robe-start).
+ Use ruby-mode if ruby isn't available (e.g. editing ruby files on
  remote systems), enh-ruby-mode otherwise.
+ Added rake, bundler, rvm, rbenv and minitest packages
+ Added $RBENV_ROOT/shims to exec-path. This should fix rbenv support
  for the ruby version display in the modeline.

modules/lang/ruby/packages.el

@@ -4,18 +4,24 @@
 ;; requires ruby ruby-lint
 
 (package! enh-ruby-mode)
-(package! rubocop)
-(package! inf-ruby)
-(package! rspec-mode)
 (package! yard-mode)
-(package! rake)
+(package! inf-ruby)
 (package! robe)
-(package! bundler)
 
 (when (featurep! :completion company)
   (package! company-inf-ruby))
 
+;; Project tools
+(package! bundler)
+(package! rake)
+(package! rubocop)
+
+;; Version management
 (when (featurep! +rbenv)
   (package! rbenv))
 (when (featurep! +rvm)
   (package! rvm))
+
+;; Testing frameworks
+(package! rspec-mode)
+(package! minitest)