These changes are arbitrarily divided into multiple commits to make it
easier to find potentially introduced bugs with git bisect.
The modifications in this commit were automatically made using the
following command:
find . -name '*.h' -exec sed -i -E 's/dbg\(\) << ("[^"{]*");/dbgln\(\1\);/' {} \;
I originally defined the bytes() method for the String class, because it
made it obvious that it's a span of bytes instead of span of characters.
This commit makes this more consistent by defining a bytes() method when
the type of the span is known to be u8.
Additionaly, the cast operator to Bytes is overloaded for ByteBuffer and
such.