refactor: use dotted LSP command names

src/ruby_host.rb

@@ -71,7 +71,7 @@ module Vamp
 
     module Lsp
       %w[definition diagnostics hover].each do |name|
-        action = Action.new("core.lsp_#{name}".freeze).freeze
+        action = Action.new("core.lsp.#{name}".freeze).freeze
         define_singleton_method(name) { action }
       end
     end