Fix doc for Neovim setting examples (#18491)

## Summary
This PR fixes an error in the example Neovim configuration on [this
documentation
page](https://docs.astral.sh/ruff/editors/settings/#configuration).
The `configuration` block should be nested under `settings`, consistent
with other properties and as outlined
[here](https://docs.astral.sh/ruff/editors/setup/#neovim).

I encountered this issue when copying the example to configure ruff
integration in my neovim - the config didn’t work until I corrected the
nesting.

## Test Plan
- [x] Confirmed that the corrected configuration works in a real Neovim
+ Ruff setup
- [x] Verified that the updated configuration renders correctly in
MkDocs
<img width="382" alt="image"
src="https://github.com/user-attachments/assets/0722fb35-8ffa-4b10-90ba-c6e8417e40bf"
/>

docs/editors/settings.md

@@ -66,9 +66,11 @@ _Using configuration file path:_
     ```lua
     require('lspconfig').ruff.setup {
       init_options = {
+        settings = {
           configuration = "~/path/to/ruff.toml"
         }
       }
+    }
     ```
 
 === "Zed"
@@ -117,6 +119,7 @@ _Using inline configuration:_
     ```lua
     require('lspconfig').ruff.setup {
       init_options = {
+        settings = {
           configuration = {
             lint = {
               unfixable = {"F401"},
@@ -135,6 +138,7 @@ _Using inline configuration:_
           }
         }
       }
+    }
     ```
 
 === "Zed"