add some documents [ci skip]

* bignum.c (Init_Bignum): [DOC] Bignum::GMP_VERSION.

* complex.c (Init_Complex): [DOC] ignore an internal class.

* dir.c (Init_Dir): [DOC] File::FNM_SYSCASE.

* file.c (rb_file_exists_p): [DOC] File.exists? is deprecated.

* object.c (rb_mod_initialize_clone): [DOC] ignore implementation
  detail.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46990 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 1 insertions, 0 deletions

diff --git a/bignum.c b/bignum.c
index 1357de0e87..08b4337262 100644
--- a/bignum.c
+++ b/bignum.c
@@ -7037,6 +7037,7 @@ Init_Bignum(void)
     rb_define_method(rb_cBignum, "even?", rb_big_even_p, 0);
 
 #ifdef USE_GMP
+    /* The version of loaded GMP. */
     rb_define_const(rb_cBignum, "GMP_VERSION", rb_sprintf("GMP %s", gmp_version));
 #endif