Updated the -I option description.
diff --git a/clang/docs/ClangCommandLineReference.rst b/clang/docs/ClangCommandLineReference.rst
index 1613c8e..699a0be 100644
--- a/clang/docs/ClangCommandLineReference.rst
+++ b/clang/docs/ClangCommandLineReference.rst
@@ -1014,9 +1014,9 @@
Flags controlling how ``#include``\s are resolved to files.
-.. option:: -I<dir>, --include-directory <arg>, --include-directory=<arg>
+.. option:: -I<dir>, --include-directory <dir>, --include-directory=<dir>
-Add directory to include search path
+Add directory <dir> to the list of include files search paths. If there are multiple -I options, these directories are searched in the order they are given before the standard system directories are searched. If the same directory is in the SYSTEM include search paths, for example if also specified with -isystem, the -I option will be ignored
.. option:: -I-, --include-barrier