bigint.c: update header commend description.
MODIFY
mrbgems/mruby-bigint/core/bigint.c
mrbgems/mruby-bigint/core/bigint.c
/**
-** @file mruby/bigint.h - Multi-precision, Integer
+** @file mruby/bigint.c - Multi-precision Integer
**
** See Copyright Notice in mruby.h
*/

MODIFY
mrbgems/mruby-bigint/core/bigint.h
mrbgems/mruby-bigint/core/bigint.h
/**
-** @file mruby/bigint.h - Multi-precision, Integer
+** @file mruby/bigint.h - Multi-precision Integer
**
** See Copyright Notice in mruby.h
*/

bigint.c: update header commend description.