Ruby

Fix [Bug #19632]: Disable external iterator for frozen enumerator (#7791)

• Fix [Bug #19632]: Disable external iterator for frozen enumerator

Currently, methods to manipulate an external iterator like #next
and #feed can be called even if a receiver of an enumerator is
frozen. However, these methods change the state of an external
iterator in an enumerator. Therefore, it seems a BUG to me, and
these methods should raise FrozenError if the receiver is frozen.

This fixed the following methods to raise FrozenError if the receiver is
frozen.

• Enumerator#next
• Enumerator#next_values
• Enumerator#peek
• Enumerator#peek_values
• Enumerator#feed
• Enumerator#rewind

• Fix a typo in the document

Thanks @Maumagnaguagno.