Remove TextNode.selectEnd

[zurfyx]

It works the same way as select() so it's redundant.

For reference, select:

if (typeof text === 'string') {
      const lastOffset = text.length;
      if (anchorOffset === undefined) {
        anchorOffset = lastOffset;
      }
      if (focusOffset === undefined) {
        focusOffset = lastOffset;
      }
    } else {
      anchorOffset = 0;
      focusOffset = 0;
    }

Added an extra test for select to ensure that select(undefined, undefined) works just like the previous selectEnd()