Docstring of `cljam.io.vcf/read-variants` lists options not supported for VCF

[alumi]

:bcf, :shallow, :raw are only supported for BCF.

cljam/src/cljam/io/vcf.clj

Lines 117 to 121 in ef213fc

	:deep - Fully parsed variant map. FORMAT, FILTER, INFO and samples columns are parsed.
	:vcf - VCF-style map. FORMAT, FILTER, INFO and samples columns are strings.
	:bcf - BCF-style map. CHROM, FILTER, INFO and :genotype contains indices to meta-info.
	:shallow - Only CHROM, POS and ref-length are parsed.
	:raw - Raw map of ByteBufers."

cljam/src/cljam/io/vcf/reader.clj

Lines 196 to 198 in ef213fc

	parse-fn (case depth
	:deep (vcf-util/variant-parser (.meta-info rdr) (.header rdr))
	:vcf identity)]

cljam/src/cljam/io/bcf/reader.clj

Lines 274 to 286 in ef213fc

	(case depth
	:deep (comp (partial bcf-map->parsed-variant
	contigs filters formats info kws)
	parse-data-line-deep)
	:vcf (comp (vcf-util/variant-vals-stringifier
	(.meta-info rdr)
	(.header rdr))
	(partial bcf-map->parsed-variant
	contigs filters formats info kws)
	parse-data-line-deep)
	:bcf parse-data-line-deep
	:shallow (partial parse-data-line-shallow contigs)
	:raw identity)))