Updated gem plugin zsh completion (gem 2.0.3).

plugins/gem/_gem

@@ -9,8 +9,9 @@ _gem_installed() {
 
 local -a _1st_arguments
 _1st_arguments=(
+  'build:Build a gem from a gemspec'
   'cert:Manage RubyGems certificates and signing settings'
-  'check:Check installed gems'
+  'check:Check a gem repository for added or missing files'
   'cleanup:Clean up old versions of installed gems in the local repository'
   'contents:Display the contents of the installed gems'
   'dependency:Show the dependencies of an installed gem'
@@ -21,7 +22,7 @@ _1st_arguments=(
   'install:Install a gem into the local repository'
   'list:Display gems whose name starts with STRING'
   'lock:Generate a lockdown list of gems'
-  'mirror:Mirror a gem repository'
+  'mirror:Mirror all gem files (requires rubygems-mirror)'
   'outdated:Display all gems that need updates'
   'owner:Manage gem owners on RubyGems.org.'
   'pristine:Restores installed gems to pristine condition from files located in the gem cache'
@@ -35,8 +36,9 @@ _1st_arguments=(
   'stale:List gems along with access times'
   'uninstall:Uninstall gems from the local repository'
   'unpack:Unpack an installed gem to the current directory'
-  'update:Update the named gems (or all installed gems) in the local repository'
+  'update:Update installed gems to the latest version'
   'which:Find the location of a library file you can require'
+  'yank:Remove a specific gem version release from RubyGems.org'
 )
 
 local expl