fix typos

Minkowski_sum_2/doc/Minkowski_sum_2/CGAL/minkowski_sum_2.h

@@ -131,8 +131,8 @@ summand `P` using the given decomposition method `no_holes_decomp`,
 unless the result is a convex polygon, in which case the nop strategy is
 applied; namely, an instance of the class template
 `Polygon_nop_decomposition_2` is used. If `P` is a polygon without holes
-to start with, then only convexity is checked. (Checking whether the
-result is convex inccurs a small overhead though.) and thendepending on
+to start with, then only convexity is checked (checking whether the
+result is convex inccurs a small overhead though). Then depending on
 the result either `no_holes_decomp` or the nop strategy is applied.
 Similarly, if the summand `Q` is of type `Polygon_with_holes_2`, then
 the function first applies the hole filteration on `Q`. If the summand

Minkowski_sum_2/doc/Minkowski_sum_2/Minkowski_sum_2.txt

@@ -172,7 +172,7 @@ polygon, the hole is irrelevant for the computation of
 can be removed (that is, filled up) before the main computation starts.
 Theoretically, we can always fill up all the holes of at least one
 polygon, transforming it into a simple polygon, and still obtain
-exactly the same Minkowski sum. Practically, we remove all holesin one
+exactly the same Minkowski sum. Practically, we remove all holes in one
 polygon whose bounding boxes are, in \f$x \f$- or \f$y \f$-direction,
 smaller than, or as large as, the bounding box of the other polygon.
 Obliterating holes in the input summands speeds up the computation of