Corrected some grammar and typo's

Add the the map image file, :kdb:`rautjarvi_map.tif`, as the     the the = double the

:kbd:`exercise_data\forestry\digitizing`                                \ = needs double backslashes to show on page

kbd:`KKJ / Finland zone 2` CRS.You will use this                 missing space before You

should en up with something similar to this:                          en = end

:kbd:`exercise_data\forestry`,                                                   \ = needs double backslashes to show on page