Set to var_features_n = None to get all genes' residuals instead of 3000 HVGs

[kieranwbbbb]

Replace
pysctransform/pysctransform.py,line 805: highly_variable = gene_attr.index[:var_features_n].tolist()
with
if var_features_n is None:
highly_variable = gene_attr.index.tolist()
else:
highly_variable = gene_attr.index[:var_features_n].tolist()