enc/shift_jis.c: Change SJIS as an alias of Windows-31J.
enc/shift_jis.c: Add PCK as an alias of Windows-31J.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@31073 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
enc/shift_jis.c: Change SJIS as an alias of Windows-31J.
enc/shift_jis.c: Add PCK as an alias of Windows-31J.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@31073 b2dd03c8-39d4-4d8f-98ff-823fe69b080e