Language Injection Support

[chenkeyv]

Use cases:

1. When write code, we may need to write some inline documents, which may contains code examples.
2. When write docs such as markdown or other format, it is causal to have a code block.
3. String literals in code may contains code from other language, such as sql query.

Attempts:

• Add multiple parsers
• Add queries of multiple languages Using queries in nvim-treesitter, eliminated hard-coded path. #12