URL in commit message can be broken in blame

Summary

URL in commit message can be broken when it is truncated in Projects::BlameController#show.

Steps to reproduce

1. Create a commit with a full URL-containing commit message on a Git repo and push them to GitLab
   • git commit -m '12345678901234567890 https://gitlab.com/gitlab-org/gitlab-ce'
2. Have an access to https://gitlab.example.com/namespace/project/blame/master/ to see that the link of the URL in commit message is broken in blame.

Example Project

• https://gitlab.com/tnir/tnir-gitlab-test-general/blame/e8517942c1fd81ff9ab0650ac7b9c6d75ae92bec/README.md

What is the current bug behavior?

URL is broken in blame.

What is the expected correct behavior?

A broken URL should not be shown.

Relevant logs and/or screenshots

Output of checks

This bug happens on GitLab.com. (GitLab 2.5.0 through 9.4.0-rc3)

Possible fixes

Use pure CSS to truncate commit messages there.

/label regression frontend backend UX ~"Community Contribution"