tools: move cmd/tools/vdoc/doc to cmd/tools/vdoc/document, so that it can be imported from other programs through -path, without conflicting with the top level doc/ folder in the main repo

tools: move cmd/tools/vdoc/doc to cmd/tools/vdoc/document, so that it can be imported from other programs through -path, without conflicting with the top level doc/ folder in the main repo #36049