Fix Yarn syntax aliases

[mataha]

Description

The main gist of this PR is conflict between .yarnrc and yarnw - both of these share source.shell.yarn even though .yarnrc is an argfile, not a shell script (see the documentation).

As an addendum I've added missing Yarn files: .yarnclean, .yarn-integrity and .yarn-metadata.json.

Motivation and Context

Invalid icon on yarnw. No icons on aforementioned files.

How Has This Been Tested?

• .yarnclean
• .yarn-integrity
• .yarn-metadata.json
• .yarnrc

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have read the CONTRIBUTING document.

[deathaxe]

ShellScript was used to achive some basic syntax highlighting even though it being clearly not a perfect choice.