vim-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: vim/vim#14992

82a579e15a

Co-authored-by: Riley Bruins <ribru17@hotmail.com>
Co-authored-by: zeertzjq <zeertzjq@outlook.com>

runtime/lua/vim/filetype.lua

@@ -985,6 +985,7 @@ local extension = {
   smt = 'smith',
   smithy = 'smithy',
   sml = 'sml',
+  smk = 'snakemake',
   spt = 'snobol4',
   sno = 'snobol4',
   sln = 'solution',
@@ -1620,6 +1621,7 @@ local filename = {
   ['/etc/slp.spi'] = 'slpspi',
   ['.slrnrc'] = 'slrnrc',
   ['sendmail.cf'] = 'sm',
+  Snakefile = 'snakemake',
   ['.sqlite_history'] = 'sql',
   ['squid.conf'] = 'squid',
   ['ssh_config'] = 'sshconfig',