`.config.get_app_dir()`: link to `click`'s orig impl on GH

piker/config.py

@@ -41,10 +41,13 @@ from .log import get_logger
 log = get_logger('broker-config')
 
 
-# XXX NOTE: taken from ``click`` since apparently they have some
-# super weirdness with sigint and sudo..no clue
-# we're probably going to slowly just modify it to our own version over
-# time..
+# XXX NOTE: taken from `click`
+# |_https://github.com/pallets/click/blob/main/src/click/utils.py#L449
+#
+# (since apparently they have some super weirdness with SIGINT and
+# sudo.. no clue we're probably going to slowly just modify it to our
+# own version over time..)
+#
 def get_app_dir(
     app_name: str,
     roaming: bool = True,