REDME: Add example output.

Author: amanagr

README.md

@@ -84,6 +84,27 @@ optional arguments:
   --fix                 Automatically fix problems where supported
 ```
 
+
+**Example Output**
+
+```
+❯ ./tools/lint
+js        | Use channel module for AJAX calls at static/js/channel.js line 81:
+js        |                 const jqXHR = $.ajax(args);
+py        | avoid subject as a var at zerver/lib/email_mirror.py line 321:
+py        |     # strips RE and FWD from the subject
+py        | Please use access_message() to fetch Message objects at zerver/worker/queue_processors.py line 579:
+py        |         message = Message.objects.get(id=event['message_id'])
+py        | avoid subject as a var at zerver/lib/email_mirror.py line 327:
+py        | Use do_change_is_admin function rather than setting UserProfile's is_realm_admin attribute directly. at file.py line 28:
+py        |             user.is_realm_admin = True
+puppet    | /usr/lib/ruby/vendor_ruby/puppet/util.rb:461: warning: URI.escape is obsolete
+hbs       | Avoid using the `style=` attribute; we prefer styling in CSS files at static/templates/group_pms.hbs line 6:
+hbs       |         <span class="user_circle_fraction" style="background:hsla(106, 74%, 44%, {{fraction_present}});"></span>
+pep8      | tools/linter_lib/custom_check.py:499:13: E121 continuation line under-indented for hanging indent
+pep8      | tools/linter_lib/custom_check.py:500:14: E131 continuation line unaligned for hanging indent
+```
+
 ### pre-commit hook mode
 
 See https://github.com/zulip/zulip/blob/master/tools/pre-commit for an