Fixed typo.

Author: shaoltan-amazon

scripts/tests/linux/tv_casting_test_sequences.py

@@ -25,7 +25,7 @@
 be stopped by providing the `STOP_APP` string as the `input_cmd`. As noted in the example below of `example_test_sequence`, the first
 four steps pertain to starting the apps while the last two are for signaling stopping the apps. 
 
-Note: `START_APP` and `STOP_APP` are reserved for signaling the starting and stopping of an apps.
+Note: `START_APP` and `STOP_APP` are reserved for signaling the starting and stopping of apps.
 
 Example:
      test_sequences = [