python: Simplify with str.removeprefix, str.removesuffix.

These are available in Python ≥ 3.9.
https://docs.python.org/3/library/stdtypes.html#str.removeprefix

Signed-off-by: Anders Kaseorg <anders@zulip.com>
(cherry picked from commit 91ade25ba3)

scripts/lib/supervisor.py

@@ -58,7 +58,8 @@ def list_supervisor_processes(
             for filter_name in filter_names:
                 # zulip-tornado:* matches zulip-tornado:9800 and zulip-tornado
                 if filter_name.endswith(":*") and (
-                    name.startswith(filter_name[:-1]) or name == filter_name[:-2]
+                    name.startswith(filter_name.removesuffix("*"))
+                    or name == filter_name.removesuffix(":*")
                 ):
                     match = True
                     break