[docs] Add "GNU binutils Replacements" section to command guide

Summary:
This splits out a section in the command guide for llvm tools that can be used as replacements for GNU tools. For pages that didn't exist, I added stub pages that can be individually filled in by followup patches.

Tested by running `ninja docs-llvm-html` and inspecting locally.

Reviewers: jhenderson, MaskRay, grimar, alexshap

Reviewed By: jhenderson, MaskRay, grimar

Subscribers: smeenai, arphaman, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D63014

llvm-svn: 363100
diff --git a/llvm/docs/CommandGuide/index.rst b/llvm/docs/CommandGuide/index.rst
index b461757..52ad316 100644
--- a/llvm/docs/CommandGuide/index.rst
+++ b/llvm/docs/CommandGuide/index.rst
@@ -20,11 +20,8 @@
    llc
    lli
    llvm-link
-   llvm-ar
    llvm-lib
    llvm-lipo
-   llvm-nm
-   llvm-objdump
    llvm-config
    llvm-cxxmap
    llvm-diff
@@ -32,12 +29,29 @@
    llvm-profdata
    llvm-stress
    llvm-symbolizer
-   llvm-addr2line
    llvm-dwarfdump
    dsymutil
    llvm-mca
    llvm-readobj
 
+GNU binutils replacements
+~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. toctree::
+   :maxdepth: 1
+
+   llvm-addr2line
+   llvm-ar
+   llvm-cxxfilt
+   llvm-nm
+   llvm-objcopy
+   llvm-objdump
+   llvm-ranlib
+   llvm-readelf
+   llvm-size
+   llvm-strings
+   llvm-strip
+
 Debugging Tools
 ~~~~~~~~~~~~~~~