Ignore files Package for VS Code

Adds syntax highlighting to 'ignore' files.

Supported files

• .gitignore: references gitignore and Ignoring-Files
• .npmignore: works just like a .gitignore references
• .dockerignore : works just like a .gitignore references
• .coffeelintignore: works just like a .gitignore.
• .slugignore: does not support negated ! patterns. Heroku - Slug Compiler
• .atomignore: works just like a .gitignore. tree-ignore
• .hgignore: references hgignore (currently only glop patterns)
• .vscodeignore: works just like a .gitignore references
• .eslintignore: works just like a .gitignore references
• .prettierignore: works just like a .gitignore references