A first tiny test commit: fix a spelling error in the documentation.
A first tiny test commit: fix a spelling error in the documentation.

rotorliu/eigen,madlib/eigen_backup,madlib/eigen_backup,mjbshaw/Eigen,mjbshaw/Eigen,mjbshaw/Eigen,rotorliu/eigen,mjbshaw/Eigen,rotorliu/eigen,madlib/eigen_backup,madlib/eigen_backup,rotorliu/eigen