Marking
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Typing an `m' followed by a lower-case character CH marks the point
to the register named CH as in Vi. In addition to these, we have
following key bindings for marking.
`m <'
Set mark at the beginning of buffer.
`m >'
Set mark at the end of buffer.
`m .'
Set mark at point (and push old mark on mark ring).
`m ,'
Jump to mark (and pop mark off the mark ring).