Update CHANGELOG.md (#4140)

Author: aciidgh

CHANGELOG.md

@@ -5,7 +5,7 @@ Swift 5.7
 
 * [#4119] 
 
-  Add a `--disable-testable-imports` flag to `swift test` with which tests are built without the testability feature (`import @tstable` disabled).
+  Add a `--disable-testable-imports` flag to `swift test` with which tests are built without the testability feature (`import @testable` disabled).
 
 Swift 5.6
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