Make parabolic terms nonexperimental

[sloede]

As discussed at the last Trixi.jl meeting, support for parabolic equations has been around long enough to remove the "experimental" warning.

[github-actions]

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (61c80ba) 83.12% compared to head (2ebae1c) 75.99%.

Additional details and impacted files

@@             Coverage Diff              @@
##           v0.6-dev    #1714      +/-   ##
============================================
- Coverage     83.12%   75.99%   -7.12%     
============================================
  Files           424      424              
  Lines         34234    34228       -6     
============================================
- Hits          28454    26011    -2443     
- Misses         5780     8217    +2437     

Flag	Coverage Δ
unittests	75.99% <ø> (-7.12%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
src/equations/compressible_navier_stokes.jl	100.00% <ø> (ø)
src/equations/compressible_navier_stokes_1d.jl	0.00% <ø> (ø)
src/equations/compressible_navier_stokes_2d.jl	41.67% <ø> (ø)
src/equations/compressible_navier_stokes_3d.jl	0.00% <ø> (ø)

... and 71 files with indirect coverage changes

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[ranocha]

Thanks!

We just mention experimental support for parabolic stuff in NEWS.md - we should clarify that it has been declared stable in v0.5.

[sloede]

Thanks!

We just mention experimental support for parabolic stuff in NEWS.md - we should clarify that it has been declared stable in v0.5.

Done in 20f97e2.

[ranocha]

Thanks!