Feature Request: Settings file per folder

[DanielTrommel]

Hi Jooy, love your module! While working with it, I thought of this way to make it even more modulair & allow for a more refined configuration:

Currently, the configuration for sidebar(s) is the one set of values, which apply to the whole sidebar. One thing I came across is that for some subfolders (for the same sidebar), I would like to have a different set of settings.

Proposal: for each folder, the module would check (while traversing) if there is a vitepress-sidebar.json file (or use the frontmatter section in index.md file that people probably already use to name the folder?); any setting in that file would override the value passed on from the parent folder.

The benefit is that the settings are contained within this folder, and one could easily move folder around. Refine per folder the file exclusions, not having to do this at the main level. Et cetera.

Looking at the code:

• The settings check at the start needs to be refactored into a method e.g. checkSettings()
• That vitepress-sidebar.json would need to be checked for existence first thing into the method, before this line at

  vitepress-sidebar/lib/index.ts

  Line 346 in 280e3b0

  let directoryFiles: string[] = readdirSync(currentDir);

• If it exists, read it, and update the inputted options
• Then, call the checkSettings() again, to check for faults

Notes:

• The scanStartPath folder (or documentRootPath if not set) could then have the same file, giving the default/initial values.
• My guess is that some settings are not allowed in subfolders, like rootGroupText and includeRootIndexFile (anything related to the root folder?)