Add Encoding#min_char_size, #max_char_size, #minmax_char_size
When implementing an IO-like object, I'd like to handle encoding correctly. To do so, I need to know the minimum and maximum character sizes for the encoding of the stream I'm reading. However, I can't find a way to access this information from Ruby (I ended up writing a gem with a native extension  to do so).
I'd like to propose adding instance methods
minmax_char_size to the
Encoding class to expose the information stored in the
Encoding::UTF_8.min_char_size # => 1 Encoding::UTF_8.max_char_size # => 6 Encoding::UTF_8.minmax_char_size # => [1, 6]