Update comments to provide more specific context

Author: ledsun

packages/npm-packages/ruby-wasm-wasi/src/vm.ts

@@ -335,8 +335,10 @@ export class RubyVM {
       this.eval(`
         # Require Bundler standalone setup
         if File.exist?("/bundle/bundler/setup.rb")
-          # Ruby can expose Gem before rubygems.rb finishes setting up its API.
-          # Load RubyGems explicitly so Bundler standalone does not see a partial Gem module.
+          # Some ruby-head + ruby.wasm revisions return from rubyInit with a partial
+          # Gem module: Gem is defined, but RubyGems is not loaded yet and its API
+          # helpers are still missing. Bundler standalone treats defined?(Gem) as
+          # sufficient, so load RubyGems explicitly before requiring its setup file.
           require "rubygems" if defined?(Gem) && !Gem.respond_to?(:ruby_api_version)
           require "/bundle/bundler/setup.rb"
         elsif File.exist?("/bundle/setup.rb")