Document for alpha release

[codingpotato]

• Use GitHub page: seedlang.github.io?
• Version number: alpha 1.0.0?
• Quick Start
• API document
• Supported Python syntax

[wixette]

• Website:
  • seedlang.github.io is good.
  • We can also publish a docs subsite under www.seedv.com/seedlang/. Or, redirect www.seedv.com/seedlang/ to seedlang.github.io sounds good too.
• Version number:
  • Either v0.3.0 or v1.0.0 looks good to me.
  • A suffix "-alpha" can be added to the version number.
• Quick start
  • There is an existing doc file at https://github.com/SeedV/SeedLang/blob/main/docs/getting_started.md. Will extend the doc to fulfill the current requirements.
• API docs:
  • Will update comments of the public interface classes of SeedLang, using JSDoc format to support auto API-doc-generation.
• Supported Python syntax features:
  • A new Markdown file under https://github.com/SeedV/SeedLang/blob/main/docs/ should work.