most uses of scm_from_locale_symbol become scm_from_utf8_symbol

most uses of scm_from_locale_symbol become scm_from_utf8_symbol

* libguile/array-handle.c:
* libguile/chars.c:
* libguile/expand.c:
* libguile/feature.c:
* libguile/goops.c:
* libguile/gsubr.c:
* libguile/instructions.c:
* libguile/load.c:
* libguile/macros.c:
* libguile/memoize.c:
* libguile/modules.c:
* libguile/options.c:
* libguile/print.c:
* libguile/smob.c:
* libguile/snarf.h: Change most uses of scm_from_locale_symbol to
  scm_from_utf8_symbol, as the symbols really are not locale-dependent.