Merge pull request #2003 from dongweiming/update-gem

Update gem completion

plugins/gem/_gem

@@ -4,10 +4,11 @@
 # gem zsh completion, based on homebrew completion
 
 _gem_installed() {
-  installed_gems=(`gem list --local --no-versions`)
+  installed_gems=(${(f)"$(gem list --local --no-versions)"})
 }
 
 local -a _1st_arguments
+
 _1st_arguments=(
   'build:Build a gem from a gemspec'
   'cert:Manage RubyGems certificates and signing settings'