restore more in setup

Author: cccclai

setup.py

@@ -666,6 +666,9 @@ def run(self):
                 "share/cmake/executorch-config.cmake",
             ),
         ]
+        # Copy all the necessary headers into include/executorch/ so that they can
+        # be found in the pip package. This is the subset of headers that are
+        # essential for building custom ops extensions.
         # TODO: Use cmake to gather the headers instead of hard-coding them here.
         # For example:
         # https://discourse.cmake.org/t/installing-headers-the-modern-way-regurgitated-and-revisited/3238/3