* README: Remove docs on "discouraged".
* configure.ac: Remove one more "discouraged" thing.
* doc/ref/api-deprecated.texi: Rename from api-discdepr.texi, and remove
sections on "discouraged".
* doc/ref/Makefile.am:
* doc/ref/guile.texi: Update referrers.
* scheme-compound.texi: Renamed to api-compound.texi.
* scheme-control.texi: Renamed to api-control.texi.
* scheme-data.texi: Renamed to api-data.texi.
* scheme-debug.texi: Renamed to api-debug.texi.
* deprecated.texi: Renamed to api-deprecated.texi.
* scheme-evaluation.texi: Renamed to api-evaluation.texi.
* ref-init.texi: Renamed to api-init.texi.
* scheme-io.texi: Renamed to api-io.texi.
* scheme-memory.texi: Renamed to api-memory.texi.
* scheme-modules.texi: Renamed to api-modules.texi.
* scheme-options.texi: Renamed to api-options.texi.
* scm.texi: Renamed to api-overview.texi.
* scheme-procedures.texi: Renamed to api-procedures.texi.
* scheme-scheduling.texi: Renamed to api-scheduling.texi.
* scheme-scm.texi: Renamed to api-scm.texi.
* scheme-smobs.texi: Renamed to api-smobs.texi.
* scheme-snarf.texi: Renamed to api-snarf.texi.
* scheme-translation.texi: Renamed to api-translation.texi.
* scheme-utility.texi: Renamed to api-utility.texi.
* debugging.texi: Renamed to scheme-debugging.texi.
* scripts.texi: Renamed to scheme-scripts.texi.
* program.texi: Renamed to libguile-program.texi.
