Ruby

Fix a line matching problem in Abbrev.abbrev(words, "prefix").

• lib/abbrev.rb (Abbrev#abbrev): A fixed string prefix pattern
  should only match the beginning of each word, not the beginning
  of every line in it.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@38027 b2dd03c8-39d4-4d8f-98ff-823fe69b080e