feat: Explicitly support URL params in string form

singer_sdk/streams/rest.py

@@ -279,18 +279,35 @@ def get_url_params(
         self,
         context: dict | None,  # noqa: ARG002
         next_page_token: _TToken | None,  # noqa: ARG002
-    ) -> dict[str, Any]:
-        """Return a dictionary of values to be used in URL parameterization.
+    ) -> dict[str, Any] | str:
+        """Return a dictionary or string of URL query parameters.
 
         If paging is supported, developers may override with specific paging logic.
 
+        If your source needs special handling and, for example, parentheses should not
+        be encoded, you can return a string constructed with
+        `urllib.parse.urlencode`_:
+
+        .. code-block:: python
+
+           from urllib.parse import urlencode
+
+           class MyStream(RESTStream):
+               def get_url_params(self, context, next_page_token):
+                   params = {"key": "(a,b,c)"}
+                   return urlencode(params, safe="()")
+
         Args:
             context: Stream partition or context dictionary.
             next_page_token: Token, page number or any request argument to request the
                 next page of data.
 
         Returns:
-            Dictionary of URL query parameters to use in the request.
+            Dictionary or encoded string with URL query parameters to use in the
+                request.
+
+        .. _urllib.parse.urlencode:
+           https://docs.python.org/3/library/urllib.parse.html#urllib.parse.urlencode
         """
         return {}
 
@@ -341,7 +358,7 @@ def prepare_request(
         """
         http_method = self.rest_method
         url: str = self.get_url(context)
-        params: dict = self.get_url_params(context, next_page_token)
+        params: dict | str = self.get_url_params(context, next_page_token)
         request_data = self.prepare_request_payload(context, next_page_token)
         headers = self.http_headers