Fix tasks.do-copy-apidocs

1. It didn't work with a non-default target specified e.g. in
   `.cargo/config`
2. It didn't work with `CARGO_MAKE_CRATE_WORKSPACE_MEMBERS`
3. It didn't work when running `cargo make docs-flow` multiple times

src/lib/descriptor/makefiles/rust.toml

@@ -736,12 +736,16 @@ private = true
 script_runner = "@shell"
 script = [
 '''
-SOURCE_DIRECTORY=${CARGO_MAKE_DOCS_ROOT_FOLDER}/target/doc
+SOURCE_DIRECTORY=${CARGO_MAKE_WORKING_DIRECTORY}/target/${CARGO_MAKE_CRATE_TARGET_TRIPLE}/doc
+if ! test -d "${SOURCE_DIRECTORY}"; then
+    SOURCE_DIRECTORY=${CARGO_MAKE_WORKING_DIRECTORY}/target/doc
+fi
 TARGET_DIRECTORY=${CARGO_MAKE_DOCS_ROOT_FOLDER}/docs/api/${CARGO_MAKE_DOCS_SUB_FOLDER}
 
 echo Source Directory: ${SOURCE_DIRECTORY}
 echo Target Directory: ${TARGET_DIRECTORY}
 
+rm -fr ${TARGET_DIRECTORY}
 mkdir -p ${TARGET_DIRECTORY}
 mv ${SOURCE_DIRECTORY}/* ${TARGET_DIRECTORY}
 '''