Returns the RDoc::Store and path relative to
mount_path for documentation at path.
# File lib/rdoc/servlet.rb, line 176
def documentation_source path
_, source_name, path = path.split '/', 3
store = @stores[source_name]
return store, path if store
store = store_for source_name
store.load_all
@stores[source_name] = store
return store, path
end