[GR-20329] Update gem commands to use --no-document option by default.

PullRequest: truffleruby/1783

Author: bjfish

CHANGELOG.md

@@ -72,6 +72,10 @@ Compatibility:
 * Implemented `Ripper` by using the C extension (#1585).
 * Fixed `refine + super` compatibility (#2039, #2048, @ssnickolay)
 
+Changes:
+
+* RubyGems gem commands updated to use the `--no-document` option by default.
+
 Performance:
 
 * Enable lazy translation from the parser AST to the Truffle AST for user code by default. This should improve application startup time (#1992).

lib/truffle/rubygems/defaults/truffleruby.rb

@@ -21,4 +21,11 @@ def self.default_dir
   # TruffleRuby has a different ABI and cannot reuse gems precompiled for MRI.
   # See https://github.com/rubygems/rubygems/issues/2945
   Gem.platforms = [Gem::Platform::RUBY]
+
+  def self.platform_defaults
+    # disable documentation by default as it takes a significant amount of time for installing gems and is rarely used
+    {
+        'gem' => '--no-document'
+    }
+  end
 end