[libc][NFC] Revise file header for tanf exhaustive test.

Author: c8ef

libc/test/src/math/exhaustive/tanf_test.cpp

@@ -1,5 +1,4 @@
-//===-- Exhaustive test for tanf
-//--------------------------------------std::cout----===//
+//===-- Exhaustive test for tanf ------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.