[PATCH v2 0/1] MR7091: windowscodecs: Make values returned from CanConvert consistent

[Jeffrey Smith (＠whydoubt)]

Any time CanConvert returns FALSE for the output parameter,
also return an appropriate failing result code.

This also adds tests for CanConvert.

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  v2: windowscodecs: Make values returned from CanConvert consistent
 
https://gitlab.winehq.org/wine/wine/-/merge_requests/7091