doco write and display

[Kevin Ryde]

I thought to add something for `write' in the manual, and to emphasise
the machine/human readability of it versus `display'.

        * scheme-io.texi (Writing): Add write, revise display.

New text, for contemplation:

 - Scheme Procedure: write obj [port]
     Send a representation of OBJ to PORT or to the current output port
     if not given.

     The output is designed to be machine readable, and can be read back
     with `read' (*note Reading::).  Strings are printed in
     doublequotes, with escapes if necessary, and characters are
     printed in `#\' notation.

 - Scheme Procedure: display obj [port]
     Send a representation of OBJ to PORT or to the current output port
     if not given.

     The output is designed for human readability, it differs from
     `write' in that strings are printed without doublequotes and
     escapes, and characters are printed as per `write-char', not in
     `#\' form.

scheme-io.texi.write-display.diff
Description: Text document