Error when renaming a file (changing only case)

When renaming a file `test/foo.hs` to `test/Foo.ts` I get an error and the rename fails:

> Unable to move/copy 'vscode-remote://dev-container+2f55736572732f64616e6e792f4465762f44616e6e792f4861736b656c6c54657374696e67/workspaces/HaskellTesting/tests/foo.hs' because target 'vscode-remote://dev-container+2f55736572732f64616e6e792f4465762f44616e6e792f4861736b656c6c54657374696e67/workspaces/HaskellTesting/tests/Foo.hs' already exists at destination.

I'm running in a container using VS Code's Remote - Containers functionality, using the following devontainer JSON:

```
{
"name": "Haskell",
"image": "haskell:8",
"settings": {
"[haskell]": {
"editor.insertSpaces": true,
}
},
"extensions": [
"haskell.haskell"
],
}
```

I had to use `haskell:8` as using `haskell:latest` complained that some components were not available on Linux using the latest version.

I'm not sure if this is an issue with the VS Code extension or something else (like the LSP server) so if this is not the right place to raise this, please point in the right direction (this is the first time I've tried to use Haskell so I'm not very familiar with the tools yet) - thanks!