Add links to GitLab Vale yaml files

[mjang]

Description

Include links to the GitLab Vale implementation

Type of change

This is info only, to provide examples for Vale users who are creating their own implementations.

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This change is 

[ChrisChinchilla]

Sorry for the delay @mjang But essentially this repo is in a period of migration into seperate repos anyway. The best things you can actually do to get the GitLab styles included in searches are the following:

• Add the vale-linter-style tag
• Refactor the style to match something like the structure you see here (https://github.com/errata-ai/Microsoft) this includes tests and all sorts of other things that make style style usable between Vale and Vale Server