Update Sources/Commands/SwiftTestCommand.swift

Co-authored-by: gmohammadi <g_mohammadi@apple.com>

Author: heckj

Sources/Commands/SwiftTestCommand.swift

@@ -1725,7 +1725,7 @@ private extension Basics.Diagnostic {
 
 /// The exit code returned to Swift Package Manager by Swift Testing when no
 /// tests matched the inputs specified by the developer (or, for the case of
-/// `swift test list`, when no tests were found.)
+/// `swift test list`, when no tests are found).
 ///
 /// Because Swift Package Manager does not directly link to the testing library,
 /// it duplicates the definition of this constant in its own source. Any changes