DOC: Fix "AdvancedMeanSquares" parameter name
DOC: Fix "AdvancedMeanSquares" parameter name

The parameter name in the manual was not according to the implementation of elastix. Issue encountered by Viktor van der Valk.

SuperElastix/elastix,SuperElastix/elastix,SuperElastix/elastix,SuperElastix/elastix,SuperElastix/elastix