Patch by Gael Guennebaud: unify fixed-size and dynamic-size Block
expressions, update documentation.
diff --git a/doc/snippets/MatrixBase_setIdentity.cpp b/doc/snippets/MatrixBase_setIdentity.cpp
index b14fcdd..17a706c 100644
--- a/doc/snippets/MatrixBase_setIdentity.cpp
+++ b/doc/snippets/MatrixBase_setIdentity.cpp
@@ -1,3 +1,3 @@
 Matrix4i m = Matrix4i::zero();
-m.fixedBlock<3,3>(1,0).setIdentity();
+m.block<3,3>(1,0).setIdentity();
 cout << m << endl;