Extra characters matched as requirements.txt package links

Summary

Lines using the compatibility operator (~=) like pytest~=3.0 get pytest~ matched as the package name.

Steps to reproduce

Open https://gitlab.com/coala/coala-utils/blob/b808a9233c51fdbe2849910c31b2c086f14fec28/test-requirements.txt#L2

Example Project

https://gitlab.com/coala/coala-utils/blob/b808a9233c51fdbe2849910c31b2c086f14fec28/test-requirements.txt#L2

What is the current bug behavior?

The line is transformed into [pytest~](https://pypi.python.org/pypi/pytest~)=3.0

What is the expected correct behavior?

It should be [pytest](https://pypi.python.org/pypi/pytest)~=3.0 instead.

Relevant logs and/or screenshots

Output of checks

This bug happens on GitLab.com

Possible fixes