About: Sets genotypes. The target genotypes can be specified as:
           ./.     .. completely missing ("." or "./.", depending on ploidy)
           ./x     .. partially missing (e.g., "./0" or ".|1" but not "./.")
           .       .. partially or completely missing
           a       .. all genotypes
           b       .. heterozygous genotypes failing two-tailed binomial test (example below)
           q       .. select genotypes using -i/-e options
           r:FLOAT .. select randomly a proportion of FLOAT genotypes (can be combined with other modes)
       and the new genotype can be one of:
           .       .. missing ("." or "./.", keeps ploidy)
           0       .. reference allele (e.g. 0/0 or 0, keeps ploidy)
           c:GT    .. custom genotype (e.g. 0/0, 0, 0/1, m/M, 0/X, ./., .;  overrides ploidy)
           i       .. invert the genotype phase (0|1 becomes 1|0)
           m       .. minor (the second most common) allele as determined from INFO/AC or FMT/GT (e.g. 1/1 or 1, keeps ploidy)
           M       .. major allele as determined from INFO/AC or FMT/GT (e.g. 1/1 or 1, keeps ploidy)
           X       .. allele with bigger read depth as determined from FMT/AD
           p       .. phase genotype (0/1 becomes 0|1)
           u       .. unphase genotype and sort by allele (1|0 becomes 0/1)
Usage: bcftools +setGT [General Options] -- [Plugin Options]
Options:
   run "bcftools plugin" for a list of common options

Plugin options:
   -e, --exclude EXPR        Exclude a genotype if true (requires -t q)
   -i, --include EXPR        include a genotype if true (requires -t q)
   -n, --new-gt TYPE         Genotypes to set, see above
   -s, --seed INT            Random seed to use with -t r [0]
   -t, --target-gt TYPE      Genotypes to change, see above

Example:
   # set missing genotypes ("./.") to phased ref genotypes ("0|0")
   bcftools +setGT in.vcf -- -t . -n 0p

   # set missing genotypes with DP>0 and GQ>20 to ref genotypes ("0/0")
   bcftools +setGT in.vcf -- -t q -n 0 -i 'GT="." && FMT/DP>0 && GQ>20'

   # set partially missing genotypes to completely missing
   bcftools +setGT in.vcf -- -t ./x -n .

   # set heterozygous genotypes to 0/0 if binom.test(nAlt,nRef+nAlt,0.5)<1e-3
   bcftools +setGT in.vcf -- -t "b:AD<1e-3" -n 0

   # force unphased heterozygous genotype if binom.test(nAlt,nRef+nAlt,0.5)>0.1
   bcftools +setGT in.vcf -- -t ./x -n c:'m/M'