language: Fix completion menu no longer prioritizes relevant items for Typescript and Python (#42065)

Closes #41672

Regressed in https://github.com/zed-industries/zed/pull/40242

Release Notes:

- Fixed issue where completion menu no longer prioritizes relevant items
for TypeScript and Python.

crates/language/src/language.rs

@@ -2324,17 +2324,19 @@ impl CodeLabel {
     }
 
     pub fn plain(text: String, filter_text: Option<&str>) -> Self {
-        Self::filtered(text, filter_text, Vec::new())
+        Self::filtered(text.clone(), text.len(), filter_text, Vec::new())
     }
 
     pub fn filtered(
         text: String,
+        label_len: usize,
         filter_text: Option<&str>,
         runs: Vec<(Range<usize>, HighlightId)>,
     ) -> Self {
+        assert!(label_len <= text.len());
         let filter_range = filter_text
             .and_then(|filter| text.find(filter).map(|ix| ix..ix + filter.len()))
-            .unwrap_or(0..text.len());
+            .unwrap_or(0..label_len);
         Self::new(text, filter_range, runs)
     }