Add a warning if report cannot detect mimetype of file.
Add a warning if report cannot detect mimetype of file.

gusevfe/snakemake,gusevfe/snakemake,pascal-git/snakemake,pascal-git/snakemake,gusevfe/snakemake,pascal-git/snakemake,gusevfe/snakemake,pascal-git/snakemake