dev-cmd/unbottled: share common parts of bottle tag regex

This makes it easier to see that the two regexes are related
and could make it easier to change them in the future if
need be.

Library/Homebrew/dev-cmd/unbottled.rb

@@ -260,12 +260,14 @@ def output_unbottled(formulae, deps_hash, noun, hash, any_named_args)
   def output_lost_bottles
     ohai ":#{@bottle_tag} lost bottles"
 
-    # $ git log --patch -G'^ +sha256.* sonoma:' --since=@{'1 week ago'}
+    bottle_tag_regex_fragment = " +sha256.* #{@bottle_tag}: "
+
+    # $ git log --patch --no-ext-diff -G'^ +sha256.* sonoma:' --since=@{'1 week ago'}
     git_log = %w[git log --patch --no-ext-diff]
-    git_log << "-G^ +sha256.* #{@bottle_tag}:"
+    git_log << "-G^#{bottle_tag_regex_fragment}"
     git_log << "--since=@{'1 week ago'}"
 
-    bottle_tag_sha_regex = /^[+-] +sha256.* #{@bottle_tag}: /
+    bottle_tag_sha_regex = /^[+-]#{bottle_tag_regex_fragment}/
 
     processed_formulae = Set.new
     commit = T.let(nil, T.nilable(String))