Copying from GitLab suggestions should not copy line numbers

Problem

For example, if I copy from !16954 (comment 224338921), I get:

      private
    
   
    14
   ​
    
   
    15
         attr_reader :cluster

Expected

      private 

      attr_reader :cluster

GitLab version

• GitLab.com
• GitLab Enterprise Edition 12.3.0-pre f79c1794