Docs for llvm-symbolizer command-line tool

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176337 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/CommandGuide/index.rst b/docs/CommandGuide/index.rst
index 9bfa964..ac8a944 100644
--- a/docs/CommandGuide/index.rst
+++ b/docs/CommandGuide/index.rst
@@ -28,6 +28,7 @@
    llvm-diff
    llvm-cov
    llvm-stress
+   llvm-symbolizer
 
 Debugging Tools
 ~~~~~~~~~~~~~~~