feat: support markdown options in markdown plugins

[coveralls]

Pull Request Test Coverage Report for Build 9124427441

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 49.759%

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Totals
Change from base Build 9123655949:	0.0%
Covered Lines:	681
Relevant Lines:	1238

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💛 - Coveralls

[pengzhanbo]

Removed plugin-markdown-image.d.ts and plugin-markdown-math.d.ts, and migrated to types.d.ts, as well as exported it by name.

Users can import types in the following ways：

/// <reference types="@vuepress/plugin-markdown-image/types" />
/// <reference types="@vuepress/plugin-markdown-math/types" />

export default {
  markdown: {
    image: {},
    math: {},
  }
}

[Mister-Hope]

I am expecting these types can be automatically loaded when users are importing those plugins.

Can we do that by importing the reference inside the node entrance?

[pengzhanbo]

I am expecting these types can be automatically loaded when users are importing those plugins.

Can we do that by importing the reference inside the node entrance?

Currently, this is the only way to ensure the correct extension of typescript types.

[Mister-Hope]

Cc @meteorlxy , So I think we might need a string unknown for markdown, or a new generic for defineUserConfig

[meteorlxy]

declare module should be allowed in a common .ts file (not only in .d.ts files).

Here's an example: https://github.com/mdit-vue/mdit-vue/blob/0a1eb8580499aa7d0db6ea7c14fad58717448fbb/packages/plugin-sfc/src/types.ts#L78