[libc++] Rename %{module} substitution to %{modules-dir}

[ldionne]

We should rename %{module} to %{modules-dir}. In fact the other variables might need a renaming too:

diff --git a/libcxx/test/configs/cmake-bridge.cfg.in b/libcxx/test/configs/cmake-bridge.cfg.in
index 0e3c3040c964..93a7a9bb8129 100644
--- a/libcxx/test/configs/cmake-bridge.cfg.in
+++ b/libcxx/test/configs/cmake-bridge.cfg.in
@@ -25,12 +25,12 @@ config.test_exec_root = os.path.join('@CMAKE_BINARY_DIR@', 'test')
 # Add substitutions for bootstrapping the test suite configuration
 import shlex
 config.substitutions.append(('%{cxx}', shlex.quote('@CMAKE_CXX_COMPILER@')))
-config.substitutions.append(('%{libcxx}', '@LIBCXX_SOURCE_DIR@'))
-config.substitutions.append(('%{include}', '@LIBCXX_GENERATED_INCLUDE_DIR@'))
-config.substitutions.append(('%{target-include}', '@LIBCXX_GENERATED_INCLUDE_TARGET_DIR@'))
-config.substitutions.append(('%{lib}', '@LIBCXX_LIBRARY_DIR@'))
-config.substitutions.append(('%{module}', '@LIBCXX_GENERATED_MODULE_DIR@'))
-config.substitutions.append(('%{test-tools}', '@LIBCXX_TEST_TOOLS_PATH@'))
+config.substitutions.append(('%{libcxx-dir}', '@LIBCXX_SOURCE_DIR@'))
+config.substitutions.append(('%{include-dir}', '@LIBCXX_GENERATED_INCLUDE_DIR@'))
+config.substitutions.append(('%{target-include-dir}', '@LIBCXX_GENERATED_INCLUDE_TARGET_DIR@'))
+config.substitutions.append(('%{lib-dir}', '@LIBCXX_LIBRARY_DIR@'))
+config.substitutions.append(('%{modules-dir}', '@LIBCXX_GENERATED_MODULE_DIR@'))
+config.substitutions.append(('%{test-tools-dir}', '@LIBCXX_TEST_TOOLS_PATH@'))
 
 # The test needs to manually rebuild the module. The compiler flags used in the
 # test need to be the same as the compiler flags used to generate the module.

This would make this a lot easier to read IMO.

Originally posted by @ldionne in #76246 (comment)