Add note about checking stash if hook interrupted

Closes sds#711

Author: sds

lib/overcommit/printer.rb

@@ -51,6 +51,7 @@ def interrupt_triggered
     def run_interrupted
       log.newline
       log.warning '⚠  Hook run interrupted by user'
+      log.warning '⚠  If files appear modified/missing, check your stash to recover them'
       log.newline
     end