fix(editor): Rank the exact type first in Java constructor completion

jdtls appends the call or body to filterText (`String(${0})`); matching
on the label instead lets typing `String` rank `String` above
`StringBuilder` and the other types sharing its sort text.

src/editor/lsp/completion.test.ts

@@ -65,6 +65,16 @@ describe("toCmCompletion", () => {
     expect(c.displayLabel).toBe("@GetMapping");
   });
 
+  it("filters on the label when filterText only adds the call or body", () => {
+    for (const filterText of ["String(${0})", "List<>()", "Runnable() {\n\t${0}\n};"]) {
+      const label = filterText.match(/^\w+/)![0];
+      const c = toCmCompletion(item({ label, filterText }));
+      expect(c.label).toBe(label);
+      expect(c.displayLabel).toBeUndefined();
+    }
+    expect(toCmCompletion(item({ label: "foo", filterText: "foo_bar" })).label).toBe("foo_bar");
+  });
+
   it("boosts preselected and demotes deprecated items", () => {
     expect(toCmCompletion(item({ preselect: true })).boost).toBe(99);
     expect(toCmCompletion(item({ deprecated: true })).boost).toBeLessThan(0);

src/editor/lsp/completion.ts

@@ -363,7 +363,9 @@ export function makeCompletion(item: CompletionItem, req: RequestContext): LspCo
     // sharing a filterText (`times(other: Int)`, `times(other: Long)`…) and the same
     // name imported from different modules need their own.
     apply:
-      cm.displayLabel || item.additionalEdits.length ? (...a: Parameters<typeof applyLsp>) => applyLsp(...a) : applyLsp,
+      cm.displayLabel || (item.filterText && item.filterText !== item.label) || item.additionalEdits.length
+        ? (...a: Parameters<typeof applyLsp>) => applyLsp(...a)
+        : applyLsp,
     info: (c: Completion) => renderInfo(c as LspCompletion),
   });
 }

src/editor/lsp/completionItems.ts

@@ -41,7 +41,7 @@ export function completionSymbolKind(kind: CompletionKind | null): string {
  * original label is shown through `displayLabel`.
  */
 export function toCmCompletion(item: CompletionItem): Completion {
-  const filter = item.filterText && item.filterText !== item.label ? item.filterText : null;
+  const filter = item.filterText && item.filterText !== item.label && !extendsLabel(item) ? item.filterText : null;
   const c: Completion = {
     label: filter ?? item.label,
     type: completionSymbolKind(item.kind),
@@ -55,6 +55,16 @@ export function toCmCompletion(item: CompletionItem): Completion {
   return c;
 }
 
+/**
+ * A `filterText` that is the label plus what the item inserts after it (jdtls
+ * `String(${0})`, `List<>()`): typing a word never reaches that part, and
+ * matching on it would rank the exact `String` like `StringBuilder`.
+ */
+function extendsLabel(item: CompletionItem): boolean {
+  const rest = item.filterText!.slice(item.label.length);
+  return item.filterText!.startsWith(item.label) && /^[^\p{L}\p{N}_$]/u.test(rest);
+}
+
 const IMPORT_SOURCE = [
   /^\s*from\s+([\w.]+)\s+import\b/m, // Python
   /^\s*import\s+(?:static\s+)?([\w.]+?)\.\w+;?\s*$/m, // Java, Kotlin