Switch to the word "might", as a drive-by change suggested in PR feedback (not related to unacceptable language)

Author: stmontgomery

Sources/Testing/Testing.docc/LimitingExecutionTime.md

@@ -18,7 +18,7 @@ Some tests may naturally run slowly: they may require significant system
 resources to complete, may rely on downloaded data from a server, or may
 otherwise be dependent on external factors.
 
-If a test may stall indefinitely or may consume too many system resources to
+If a test might stall indefinitely or might consume too many system resources to
 complete effectively, consider setting a time limit for it so that it's marked
 as failing if it runs for an excessive amount of time. Use the
 ``Trait/timeLimit(_:)-4kzjp`` trait as an upper bound: