specify which MSH format: Gmsh's
specify which MSH format: Gmsh's

#77 reported confusion of MSH with a similarly named format used by ANSYS Fluent.  The link points to Gmsh, but here's a more explicit visual indication.

The opportunity was also taken to update the link to the Gmsh MSH definition; old URL was still valid but new one is tidier.
nschloe/meshio