add pinned taps count to brew tap-info

Library/Homebrew/cmd/tap-info.rb

@@ -24,12 +24,15 @@ module Homebrew
       tap_count = 0
       formula_count = 0
       command_count = 0
+      pinned_count = 0
       Tap.each do |tap|
         tap_count += 1
         formula_count += tap.formula_files.size
         command_count += tap.command_files.size
+        pinned_count += 1 if tap.pinned?
       end
       info = "#{tap_count} tap#{plural(tap_count)}"
+      info += ", #{pinned_count} pinned"
       info += ", #{formula_count} formula#{plural(formula_count, "e")}"
       info += ", #{command_count} command#{plural(command_count)}"
       info += ", #{Tap::TAP_DIRECTORY.abv}" if Tap::TAP_DIRECTORY.directory?