docs: correct the decompress and decrypt cancellation remarks

[matt-edmondson]

Corrects five XML doc remarks that shipped in 2.2.0 and are already on NuGet. Callers reading the current docs are told the wrong reason to distrust a partial destination.

What was wrong

TryDecompressAsync (Gzip, Deflate, ZLib, Brotli) and TryDecryptAsync (AES) each claimed that cancellation "still flushes the trailer" or "still flushes the final block". On those paths nothing is flushed to the destination at all. The wrapping stream takes the source:

GZipStream gzipStream = new(compressedData, CompressionMode.Decompress, leaveOpen: true);
await using (gzipStream.ConfigureAwait(false))
{
    await gzipStream.CopyToAsync(destination, 81920, cancellationToken).ConfigureAwait(false);
}

Disposal tears down the decompressor over the source. The destination only ever sees CopyToAsync output.

What it says now

The conclusion was always right, so the guidance to treat the destination as invalid unless the method returns true is unchanged. Only the justification is replaced: decompressed bytes and recovered plaintext have no structure of their own, so a truncated destination can't be told apart from a complete one by inspecting it. Each remark also now notes that the stream wraps the source, which is what makes the trailer irrelevant here.

What is deliberately untouched

The compress and encrypt remarks in the same five files. Those are accurate, because there the stream really does wrap the destination and disposal really does write the trailer or the final cipher block. That asymmetry is the whole point, and it is why only one of each pair changed.

Risk

None. Documentation only, no behavior change. Confirmed no test asserted the wrong claim, so nothing needed rewriting alongside it. Full solution builds clean, 0 warnings and 0 errors under warnings-as-errors.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud