Cannot for the life of me configure formatting

Nobody has claimed this yet.

### How are you using the lua-language-server?

Visual Studio Code Extension (sumneko.lua)

### Which OS are you using?

MacOS

### What is the issue affecting?

Formatting

### Expected Behaviour

Formatting adds 6 spaces for indentation.

### Actual Behaviour

Formatting adds the default 2.

### Reproduction steps

I have it set as the default formatter in my `settings.json`:

```
"[lua]": {
"editor.quickSuggestions": {
"other": true,
"comments": true,
"strings": true
},
"editor.tabCompletion": "on",
"editor.quickSuggestionsDelay": 1,
"editor.suggest.snippetsPreventQuickSuggestions": false,
"editor.defaultFormatter": "sumneko.lua",
},
```

I put in `.luarc.json` in my workspace:

```
{
"Lua.format.defaultConfig": {
"indent_style": "space",
"indent_size": "6"
}
}
```

But no luck,

I put in `.vscode/settings.json` in my workspace:

```
{
"Lua.format.defaultConfig": {
"indent_style": "space",
"indent_size": "6"
}
}
```

I try various ways of adding this to the core `settings.json` used by VSCode, either adding it under the `[lua]` entry, or as a top level entry, but no luck.

What am I missing?!

thanks!

### Additional Notes

_No response_

### Log File

_No response_

Reproduce the formatting behavior in Visual Studio Code using the shown settings.json, .luarc.json, and .vscode/settings.json configurations. Trace how the language server reads the formatting configuration and determine why indent_size 6 is ignored; done means the documented workspace configuration produces six-space indentation.

Written by the indexing model from the issue text.