fix(47043): as const cast wrong colour when using typescript 4.5.2 (#47066)

Author: a-tarasyuk

src/services/classifier.ts

@@ -1075,6 +1075,10 @@ namespace ts {
                             }
                             return;
                     }
+
+                    if (isConstTypeReference(token.parent)) {
+                        return ClassificationType.keyword;
+                    }
                 }
                 return ClassificationType.identifier;
             }

tests/cases/fourslash/semanticClassificationConstAssertion.ts

@@ -0,0 +1,20 @@
+/// <reference path="fourslash.ts"/>
+
+////1 as const;
+
+const c1 = classification("original");
+verify.syntacticClassificationsAre(
+    c1.numericLiteral("1"),
+    c1.keyword("as"),
+    c1.keyword("const"),
+    c1.punctuation(";")
+);
+
+
+const c2 = classification("2020");
+verify.syntacticClassificationsAre(
+    c2.semanticToken("number", "1"),
+    c2.semanticToken("keyword", "as"),
+    c2.semanticToken("keyword", "const"),
+    c2.semanticToken("punctuation", ";")
+);