improve keyword suggestions when completing partial keyword

pkg/analysis_server/test/services/completion/keyword_computer_test.dart

Index: pkg/analysis_server/test/services/completion/keyword_computer_test.dart
diff --git a/pkg/analysis_server/test/services/completion/keyword_computer_test.dart b/pkg/analysis_server/test/services/completion/keyword_computer_test.dart
index 1f0725ecbe6a12b33a1cc61f5fa584f302af67a7..822bfe4bdfe2d000b9580f07862bec8cf452cc20 100644
--- a/pkg/analysis_server/test/services/completion/keyword_computer_test.dart
+++ b/pkg/analysis_server/test/services/completion/keyword_computer_test.dart
@@ -145,4 +145,37 @@ class KeywordComputerTest extends AbstractCompletionTest {
             'typedef',
             'var']);
   }
+
+  test_partial_class() {
+    addTestSource('cl^');
+    expect(computeFast(), isTrue);
+    assertSuggestKeywords(
+        [
+            'abstract',
+            'class',
+            'const',
+            'export',
+            'final',
+            'import',
+            'library',
+            'part',
+            'typedef',
+            'var']);
+  }
+
+  test_partial_class2() {
+    addTestSource('library a; cl^');
+    expect(computeFast(), isTrue);
+    assertSuggestKeywords(
+        [
+            'abstract',
+            'class',
+            'const',
+            'export',
+            'final',
+            'import',
+            'part',
+            'typedef',
+            'var']);
+  }
 }