string.c: [DOC] rb_str_hash_m

* string.c (rb_str_hash_m): [DOC] hash value depends on the
  encoding too.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45328 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
[DOC] add links to `Object#hash`

add links to `Object#hash` to each #`hash` methods rdocs.
[Fixes GH-567]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45329 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
bignum.c: adjust condtions

* bignum.c (maxpow{16,32,64,128}_{exp,num}): adjust preprocessor
  condtions to maxpow_in_bdigit_dbl().

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45330 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
range.c: unused function

* range.c (SET_EXCL): remove no longer used function.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45331 b2dd03c8-39d4-4d8f-98ff-823fe69b080e