fix TSFunctionType failing on TypeParameters (#1394)

src/printer.js

@@ -1631,8 +1631,14 @@ function genericPrintNoParens(path, options, print, args) {
       if (needsParens) {
         parts.push("(");
       }
-
-      parts.push(path.call(print, "typeParameters"));
+    
+      if (n.typeParameters && n.typeParameters.length) {
+        parts.push(
+          "<",
+          join(", ", path.map(print, "typeParameters")),
+          ">"
+        )
+      }
 
       parts.push(printFunctionParams(path, print, options));
 

tests/typescript/conformance/types/functions/__snapshots__/jsfmt.spec.js.snap

@@ -565,6 +565,13 @@ function fn5() {}
 
 `;
 
+exports[`functionTypeTypeParameters.ts 1`] = `
+type FuncWithTypeParameter = <T, P>() => {};
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+type FuncWithTypeParameter = <T, P>() => {};
+
+`;
+
 exports[`parameterInitializersForwardReferencing.ts 1`] = `
 function left(a, b = a, c = b) {
     a;

tests/typescript/conformance/types/functions/functionTypeTypeParameters.ts

@@ -0,0 +1 @@
+type FuncWithTypeParameter = <T, P>() => {};