feat(lsp)!: remove .vscode/settings.json support in favour of codesettings.nvim

[mrcjkb]

Closes #863.

Removing .vscode/settings.json support in favour of the codesettings.nvim plugin.

[github-actions]

Review Checklist

Does this PR follow the Contribution Guidelines? Following is a partial checklist:

Proper conventional commit scoping:

• For example, fix(lsp): some lsp-related bugfix

• Pull request title has the appropriate conventional commit prefix.

If applicable:

• Tested
  • Tests have been added.
  • Tested manually (Steps to reproduce in PR description).
• Updated documentation.

[mrjones2014]

I tested codesettings.nvim against release v7.0.9 and the global hook with before_init now works, no special config for rustaceanvim needed

vim.g.rustaceanvim = {
  server = {
    -- rely on codesettings.nvim to load workspace settings
    load_vscode_settings = false,
    ---@type lsp.rust_analyzer
    default_settings = {
      -- your global settings go here
    },
  },
}

Updated my docs here: mrjones2014/codesettings.nvim#99

[mrcjkb]

I'll leave this PR open for a while, as the nvim 0.12 release is nearing. Then I can put 2 breaking changes in one major version bump when I drop nvim 0.11 support.