try not to use r", maybe that will fix the build

plugin/core/signature_help.py

@@ -116,7 +116,7 @@ def _render_label(self, view: sublime.View, signature: SignatureInformation) ->
                     # route relies on the client being smart enough to figure where the parameter is inside of
                     # the signature label. The above case where the label is a tuple of (start, end) positions is much
                     # more robust.
-                    label_match = re.search(r"\W{}\W".format(rawlabel), label[prev:])
+                    label_match = re.search("\\W{}\\W".format(rawlabel), label[prev:])
                     start = -1
                     if label_match:
                         start = label_match.start() + 1  # skip the first matched \W by adding + 1