cmake: Improve CMake comments

Co-authored-by: Wilson <[email protected]>

Author: jorisv

bindings/python/CMakeLists.txt

@@ -161,9 +161,10 @@ if(BUILD_PYTHON_INTERFACE)
   set(PINOCCHIO_PYTHON_INSTALL_DIR ${ABSOLUTE_PYTHON_SITELIB}/${PROJECT_NAME})
 
   pinocchio_python_bindings_specific_type(default)
-  # Precompile Headers are used to speed up compilation of bindings. Tests were performed also on
-  # pinocchio_default, and there was no gain in using pch for the main lib, compared to the gain for
-  # bindings. PCH are used to precompile headers of other scalar types as well.
+  # Precompiled headers are used to speed up compilation of the Python bindings. We have also tested 
+  # precompiling headers for the main library's `pinocchio_default` target, but the time gain there was
+  # negligible compared to the time gained in the Python bindings.
+  # We also precompile headers for other scalar types as well.
   target_precompile_headers(${PYWRAP}_default PRIVATE
                             ${PROJECT_SOURCE_DIR}/include/pinocchio/bindings/python/pch.hpp)
   set(PYTHON_LIB_NAME "${PYWRAP}_default")