[llvm-install-name-tool] Update the command-line guide

Author: Alexander Shaposhnikov

llvm/docs/CommandGuide/llvm-install-name-tool.rst

@@ -43,6 +43,10 @@ the same `<rpath>` value.
  times to delete multiple rpaths. Throws an error if ``<rpath>`` is not listed in
  the binary.
 
+.. option:: --help, -h
+
+ Print a summary of command line options.
+
 .. option:: -id <name>
 
  Change shared library's identification name under LC_ID_DYLIB to ``<name>`` in the
@@ -55,6 +59,10 @@ the same `<rpath>` value.
  multiple times to change multiple rpaths. Throws an error if ``<old_rpath>`` is not listed
  in the binary or ``<new_rpath>`` is already listed in the binary.
 
+.. option:: --version, -V
+
+ Display the version of the :program:`llvm-install-name-tool` executable.
+
 EXIT STATUS
 -----------