refactor: align Ruby host with RuboCop while retaining double quotes

examples/config.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # @param config [Vamp::Config]
 Vamp.configure do |config|
   config.leader = "space"
@@ -7,12 +9,6 @@ Vamp.configure do |config|
   config.file_picker_view = "tree"
   config.bind "ctrl+j", config.core.down, mode: config.modes.selection
   config.bind "ctrl+k", config.core.up, mode: config.modes.selection
-  config.bind "h", config.core.left, mode: config.modes.tree
-  config.bind "j", config.core.down, mode: config.modes.tree
-  config.bind "k", config.core.up, mode: config.modes.tree
-  config.bind "l", config.core.right, mode: config.modes.tree
-  config.bind "ctrl+h", config.core.left, mode: config.modes.tree
-  config.bind "ctrl+l", config.core.right, mode: config.modes.tree
   config.plugin "plugins/greeting.rb"
   # Native LSP is disabled by default; install a server and explicitly opt in.
   # config.lsp["rust"] = true # built-in rust-analyzer preset

examples/plugins/greeting.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 Vamp.plugin "greeting", requires: ["text"]
 
 # @param editor [Vamp::Editor]