allow named select case

[dbroemmel]

trafficstars

I've come across misalignments when select case blocks included a name: with them, e.g.

case_label: select case (r)
case (1) case_label
   <code>
case (2) case_label
   <more code>
end select case case_label

Currently fprettify would not recognise those and not indent <code> or <more code>.

I've expanded what I guessed needs expanding and amended a single, simple test within example.f90. I've not checked other select statements apart from select case. The checksum is also updated accordingly.