docs: drop support for v3.x grammar
Migrate Build System to ESP-IDF 5.0
===================================
+Migrating from make to cmake
+----------------------------
+
Please follow the :ref:`build system <migrating_from_make>` guide for migrating make-based projects no longer supported in ESP-IDF v5.0.
+
+Update fragment file grammar
+----------------------------
+
+Please follow the :ref:`migrate linker script fragment files grammar<ldgen-migrate-lf-grammar>` chapter for migrating v3.x grammar to the new one.
