docs(cmake): Fix typo in reference to EXTRA_COMPONENT_DIRS

This fixes a typo in a comment that references EXTRA_COMPONENT_DIRS in
project.cmake.

Author: fermino

tools/cmake/project.cmake

@@ -567,8 +567,8 @@ endfunction()
 
 macro(project project_name)
     # Initialize project, preparing COMPONENTS argument for idf_build_process()
-    # call later using external COMPONENT_DIRS, COMPONENTS_DIRS, EXTRA_COMPONENTS_DIR,
-    # EXTRA_COMPONENTS_DIRS, COMPONENTS, EXLUDE_COMPONENTS, TEST_COMPONENTS,
+    # call later using external COMPONENT_DIRS, COMPONENTS_DIRS, EXTRA_COMPONENT_DIRS,
+    # EXTRA_COMPONENT_DIRS, COMPONENTS, EXLUDE_COMPONENTS, TEST_COMPONENTS,
     # TEST_EXLUDE_COMPONENTS, TESTS_ALL, BUILD_TESTS
     __project_init(components test_components)