[docs] [tools] Fix see also links

Summary: Changes "see also" links to use :manpage: instead of plain text or the form `name|name` which was being treated literally, not as a link.

Reviewers: jhenderson, rupprecht

Reviewed By: jhenderson

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D63970

llvm-svn: 365159
diff --git a/llvm/docs/CommandGuide/bugpoint.rst b/llvm/docs/CommandGuide/bugpoint.rst
index 9cf4f02..971807e 100644
--- a/llvm/docs/CommandGuide/bugpoint.rst
+++ b/llvm/docs/CommandGuide/bugpoint.rst
@@ -194,4 +194,4 @@
 SEE ALSO
 --------
 
-opt|opt
+:manpage:`opt(1)`