Merge pull request #8340 from hughbe/swiftdoc-delete

Remove old .swiftdoc file before creating new .swiftdoc file
diff --git a/cmake/modules/SwiftSource.cmake b/cmake/modules/SwiftSource.cmake
index 1724fff..8548fbc 100644
--- a/cmake/modules/SwiftSource.cmake
+++ b/cmake/modules/SwiftSource.cmake
@@ -491,6 +491,8 @@
         COMMAND
           "${CMAKE_COMMAND}" "-E" "remove" "-f" "${module_file}"
         COMMAND
+          "${CMAKE_COMMAND}" "-E" "remove" "-f" "${module_doc_file}"
+        COMMAND
           "${PYTHON_EXECUTABLE}" "${line_directive_tool}" "@${file_path}" --
           "${swift_compiler_tool}" "-emit-module" "-o" "${module_file}" ${swift_flags}
           "@${file_path}"