patch 9.1.0486: filetype: Snakemake files are not recognized

patch 9.1.0486: filetype: Snakemake files are not recognized

Problem:  filetype: Snakemake files are not recognized
Solution: Detect '*.smk' and Snakefile files as snakemake filetype
          (Riley Bruins)

See:
https://snakemake.readthedocs.io/en/stable/snakefiles/deployment.html#distribution-and-reproducibility

closes: #14992

Co-authored-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Riley Bruins <ribru17@hotmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>