Update DMQMC section of the manual
Update DMQMC section of the manual

Update DMQMC input option, including fixing typos and maths formatting,
and also filling in/correcting explanations.

ruthfranklin/hande,hande-qmc/hande,hande-qmc/hande,hande-qmc/hande,hande-qmc/hande,hande-qmc/hande