Docs: Fix the title underline too short.

llvm-svn: 332245
diff --git a/llvm/docs/ProgrammersManual.rst b/llvm/docs/ProgrammersManual.rst
index aef0d20..4098f38 100644
--- a/llvm/docs/ProgrammersManual.rst
+++ b/llvm/docs/ProgrammersManual.rst
@@ -1021,7 +1021,7 @@
 .. _DEBUG:
 
 The ``LLVM_DEBUG()`` macro and ``-debug`` option
--------------------------------------------
+------------------------------------------------
 
 Often when working on your pass you will put a bunch of debugging printouts and
 other code into your pass.  After you get it working, you want to remove it, but