Make notation for Scheme repeated arguments more consistent in manual.

Make notation for Scheme repeated arguments more consistent in manual.

* doc/ref/api-compound.texi
* doc/ref/api-control.texi
* doc/ref/api-data.texi
* doc/ref/api-debug.texi
* doc/ref/api-evaluation.texi
* doc/ref/api-macros.texi
* doc/ref/api-memory.texi
* doc/ref/api-modules.texi
* doc/ref/api-procedures.texi
* doc/ref/api-regex.texi
* doc/ref/api-scheduling.texi
* doc/ref/api-utility.texi
* doc/ref/goops.texi
* doc/ref/match.texi
* doc/ref/misc-modules.texi
* doc/ref/posix.texi
* doc/ref/r6rs.texi
* doc/ref/scheme-using.texi
* doc/ref/srfi-modules.texi
* doc/ref/sxml-match.texi: Make notation for Scheme repeated arguments more
  consistent in manual.