"function" without followed by "(" should be considered as Global function type

Author: Yui T

src/compiler/checker.ts

@@ -6855,6 +6855,7 @@ namespace ts {
                     case "Object":
                         return anyType;
                     case "Function":
+                    case "function":
                         return globalFunctionType;
                     case "Array":
                     case "array":

src/compiler/parser.ts

@@ -6075,7 +6075,10 @@ namespace ts {
                     case SyntaxKind.OpenBraceToken:
                         return parseJSDocRecordType();
                     case SyntaxKind.FunctionKeyword:
-                        return parseJSDocFunctionType();
+                        if (lookAhead(nextTokenIsOpenParen)) {
+                            return parseJSDocFunctionType();
+                        }
+                        break;
                     case SyntaxKind.DotDotDotToken:
                         return parseJSDocVariadicType();
                     case SyntaxKind.NewKeyword: