Fixed build warnings / errors

Author: gfoidl

src/ImageSharp/Formats/Jpeg/JpegDecoderCore.cs

@@ -125,7 +125,7 @@ public JpegDecoderCore(JpegDecoderOptions options)
     }
 
     /// <summary>
-    /// The only supported precision
+    /// Gets the only supported precisions
     /// </summary>
     // Refers to assembly's static data segment, no allocation occurs.
     private static ReadOnlySpan<byte> SupportedPrecisions => new byte[] { 8, 12 };

src/ImageSharp/Formats/Webp/Lossy/WebpLossyDecoder.cs

@@ -361,6 +361,9 @@ private void ReconstructRow(Vp8Decoder dec)
             }
         }
 
+        Span<int> scratch = stackalloc int[16];
+        Span<byte> scratchBytes = stackalloc byte[4];
+
         // Reconstruct one row.
         for (int mbx = 0; mbx < dec.MbWidth; mbx++)
         {
@@ -399,9 +402,6 @@ private void ReconstructRow(Vp8Decoder dec)
                 topYuv.V.CopyTo(yuv[(vOff - WebpConstants.Bps)..]);
             }
 
-            Span<int> scratch = stackalloc int[16];
-            Span<byte> scratchBytes = stackalloc byte[4];
-
             // Predict and add residuals.
             if (block.IsI4x4)
             {

src/ImageSharp/Formats/Webp/WebpDecoderCore.cs

@@ -228,7 +228,7 @@ private WebpImageInfo ReadVp8Info(BufferedReadStream stream, ImageMetadata metad
     /// <param name="chunkType">The chunk type.</param>
     /// <param name="features">The webp image features.</param>
     /// <param name="ignoreAlpha">For identify, the alpha data should not be read.</param>
-    /// <param name="buffer">Temporary buffer.</param></param>
+    /// <param name="buffer">Temporary buffer.</param>
     /// <returns>true, if its a alpha chunk.</returns>
     private bool ParseOptionalExtendedChunks(
         BufferedReadStream stream,