Allow specifying a custom limit for /search results (#12423)

<img width="497" alt="image"
src="https://github.com/zed-industries/zed/assets/482957/94e94326-fb3c-4f9b-b4d9-7dd6f6f8d537">


e.g.

```
/search --9 foobar
```

Release Notes:

- N/A

crates/language/src/language.rs

@@ -535,7 +535,7 @@ async fn try_fetch_server_binary<L: LspAdapter + 'static + Send + Sync + ?Sized>
     binary
 }
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, Default, PartialEq, Eq)]
 pub struct CodeLabel {
     /// The text to display.
     pub text: String,
@@ -1540,6 +1540,15 @@ impl CodeLabel {
         }
         result
     }
+
+    pub fn push_str(&mut self, text: &str, highlight: Option<HighlightId>) {
+        let start_ix = self.text.len();
+        self.text.push_str(text);
+        let end_ix = self.text.len();
+        if let Some(highlight) = highlight {
+            self.runs.push((start_ix..end_ix, highlight));
+        }
+    }
 }
 
 impl Ord for LanguageMatcher {