Explain --reproduce option

I think --reproduce is no longer a debug-only option but a useful
option that a common user may want to use. So, this patch updates
the description of the option in the manual page.

Differential Revision: https://reviews.llvm.org/D60557

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@369740 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/ld.lld.1 b/docs/ld.lld.1
index f971157..f2578ba 100644
--- a/docs/ld.lld.1
+++ b/docs/ld.lld.1
@@ -407,8 +407,10 @@
 .Fl -push-state.
 .It Fl -relocatable , Fl r
 Create relocatable object file.
-.It Fl -reproduce Ns = Ns Ar value
-Dump linker invocation and input files for debugging.
+.It Fl -reproduce Ns = Ns Ar path
+Write a tar file containing all input files and a text file describing the link invocation to
+.Ar path,
+so that you can easily re-run the linker with the same options and input files.
 .It Fl -retain-symbols-file Ns = Ns Ar file
 Retain only the symbols listed in the file.
 .It Fl -rpath Ns = Ns Ar value , Fl R Ar value