Document position advancement in MemoryStream.WriteByte

[oii-nasif]

Fixes #10163

Summary

• Added documentation to MemoryStream.WriteByte to clarify that the method advances the stream's position by one
  byte upon successful write
• Mirrors the documentation style used in the Write method for consistency

Details

The WriteByte() method documentation was missing information about position advancement, which was present in
the Write() method documentation. This omission could confuse developers about how the stream's position changes
when using this method.

Changes Made

Added the following clarification to the Remarks section:

If the write operation is successful, the current position within the stream advances by one byte. If an
exception occurs, the current position within the stream is unchanged.

This matches the documentation pattern used in Write() and provides developers with clear expectations about
position behavior.