Apply suggestion from @jgmcnutt

Co-authored-by: jgmcnutt <jgmcnutt@me.com>

Author: grynspan

Sources/Testing/Testing.docc/Attachments.md

@@ -101,7 +101,7 @@ struct SalesReport { ... }
 ```
 
 If you don't specify an image format when attaching an image to a test, the
-testing library infers which format to use based on the preferred name you pass.
+testing library selects the format to use based on the preferred name you pass.
 
 ### Attach other values