Update pathio_writebytesasync_1599878576.md to say it writes the entire buffer, not just a single byte

The documentation description is clearly wrong -- obviously a method "WriteBytes" that takes an array will write all of the bytes, not just one.

Author: pedasmith

windows.storage/pathio_writebytesasync_1599878576.md

@@ -10,7 +10,7 @@ public Windows.Foundation.IAsyncAction WriteBytesAsync(System.String absolutePat
 # Windows.Storage.PathIO.WriteBytesAsync
 
 ## -description
-Writes a single byte of data to the file at the specified path or Uniform Resource Identifier (URI).
+Writes an entire array of bytes of data to the file at the specified path or Uniform Resource Identifier (URI).
 
 ## -parameters
 ### -param absolutePath