Add option to checkTextForURL on each character on each text-change

[nate-knight]

Currently, quill-magic-url checks the text for URL patterns :

• after whitespace is added
• after the quill editor is blurred

Some editors such (eg. Mac Notes, Evernote) only do transforms after whitespace is entered. Others, such as Slack perform URL transformations as soon as a valid URL is typed (without whitespace).

It would be helpful to add an optional parameter to quill-magic-url to perform the checkTextForURL operation on each text-change, so the consumer can decide which approach is best for their particular use-case.