Fix finding injection layer in tree cursor with nested layers (helix-…

…editor#11365)

The `take_while` should limit the layers to those that can match the
input range so we don't always scan the entire `injection_layers`. We
can limit `depth == 1` layers to those that start before the search
`end`. Deeper layers overlap with shallower layers though so we need
to allow those layers as well in the `take_while`.

For example

```vue
<script setup lang="ts">
const foo = 'bar'.match(/foo/);
const bar = foo;
</script>
```

L2 and L3 are a typescript layer and the `/foo/` part is a small regex
layer. If you used `A-o` before the regex layer you would select the
entire typescript layer. The search in `layer_id_containing_byte_range`
would not consider the typescript layer since the regex layer comes
earlier in `injection_ranges` and that layer's start is after `end`.
The regex layer has a depth of `2` though so the change in this commit
allows scanning through that layer.

Co-authored-by: Pascal Kuthe <pascalkuthe@pm.me>

helix-core/src/syntax/tree_cursor.rs

@@ -204,7 +204,7 @@ impl<'a> TreeCursor<'a> {
 
         self.injection_ranges[start_idx..]
             .iter()
-            .take_while(|range| range.start < end)
+            .take_while(|range| range.start < end || range.depth > 1)
             .find_map(|range| (range.start <= start).then_some(range.layer_id))
             .unwrap_or(self.root)
     }