Revise fortran example

[robertodr]

Slight modifications to the Fortran_host.f90, to reflect the version written up int the paper, and Fortran_host-modules.f90 source files, for formatting.

The formatter I am using is fprettify:

fprettify -i 2 -w 2

Status

• Ready to go

[MinazoBot]

Generated by 🚫 Danger

[codecov]

Codecov Report

Merging #149 into release/1.2.Z will not change coverage.
The diff coverage is n/a.

@@              Coverage Diff               @@
##           release/1.2.Z     #149   +/-   ##
==============================================
  Coverage          69.81%   69.81%           
==============================================
  Files                 92       92           
  Lines               5625     5625           
==============================================
  Hits                3927     3927           
  Misses              1698     1698

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[arnfinn]

Impossible to see what have been changed, since the file has been formated:)