Display Rubocop cop names in output by default

This makes it easier to know which cop to disable if it is a nuisance.

Author: sds

Diff for: CHANGELOG.md

@@ -55,6 +55,8 @@
 * Restore file modification times of unstaged files in addition to staged files
   in pre-commit hook runs
 * Change default value for `problem_on_unmodified_line` from `warn` to `report`
+* Update `Rubocop` pre-commit hook to pass `--display-cop-names` flag so
+  cop names appear in output
 
 ## 0.23.0
 

Diff for: config/default.yml

@@ -339,7 +339,7 @@ PreCommit:
     enabled: false
     description: 'Analyzing with Rubocop'
     required_executable: 'rubocop'
-    flags: ['--format=emacs', '--force-exclusion']
+    flags: ['--format=emacs', '--force-exclusion', '--display-cop-names']
     install_command: 'gem install rubocop'
     include:
       - '**/*.gemspec'