Help for option to output geneBiotype from `geneInfo.tab` to `features.tsv`.

[galaxy001]

$ head -n6 genome/geneInfo.tab
332285
ENSMUSG00000051951	Xkr4	protein_coding
ENSMUSG00000089699	Gm1992	lncRNA
ENSMUSG00000102331	Gm19938	lncRNA
ENSMUSG00000102343	Gm37381	lncRNA
ENSMUSG00000025900	Rp1	protein_coding

$ head -n6 features.tsv
ENSMUSG00000051951	Xkr4	Gene Expression
ENSMUSG00000089699	Gm1992	Gene Expression
ENSMUSG00000102331	Gm19938	Gene Expression
ENSMUSG00000102343	Gm37381	Gene Expression
ENSMUSG00000025900	Rp1	Gene Expression
ENSMUSG00000025902	Sox17	Gene Expression

soloOutFormatFeaturesGeneField3 can only set field3 to a fixed string, it is helpful to copy the original biotype.
Would you make --soloOutFormatFeaturesGeneField3 COPY or sth. like this ?