Proposal: Generate Template Guide from TypeScript code comments

[imWildCat]

Currently, we are writing this guide manually. However, in the future with more interactions of this project, there might be inconsistency between the code logic and this documentation.

By analyzing our code, we can generate documentations automatically, like our API doc: https://github.com/microsoft/ts-gyb/blob/main/documentation/generated/interfaces/LanguageRenderingConfiguration.md