fix typo

Co-authored-by: Denis Lehmann <denis.lehmann@4am-robotics.com>

README.md

@@ -138,7 +138,7 @@ sessions:
 - `user: string` (optional, default: robot): Target user of the `tmux` session.
 - `wait_for_core: bool` (optional, default: true): Starts the session only after `roscore` is available.
 - `prio: int` (optional, default: 10): Priority of starting the session. Sessions with the same priority start concurrently. Smaller numbers have higher priority.
-- `stop_prio: int` (optional, default: `prio`): Priority of stopping the session. Sessions with the same priority stop concurrently. Higher number have higher priority.
+- `stop_prio: int` (optional, default: `prio`): Priority of stopping the session. Sessions with the same priority stop concurrently. Higher numbers have higher priority.
 - `locked: bool` (optional, default: false): Locked sessions won't be closed on `stop` or `restart` (only if forced).
 - `pre_condition: string` (optional): Bash command used as a condition that must be fulfilled before the session can start.