Formatting of FASTQ paths in config is critical

[ijhoskins]

Not really an issue, just a quirk of setting up the config yaml file properly.

The following formatting does not work and leads to strange mappings in work/tmp/correspondence.txt and consequently an error similar to this (if do_check_file_existence : true):

ERROR ~ assert this_file.exists()
       |         |
       |         false
       /scratch/users/ihoskins/TEC/s

Incorrect formatting:

fastq:
AAVS1_KO_rep1: /scratch/users/ihoskins/TEC/TEC_1_R1.fq.gz

Correct formatting:

fastq:
AAVS1_KO_rep1:
- /scratch/users/ihoskins/TEC/TEC_1_R1.fq.gz

Conversely, the newline and hyphen is not required for specifying the reference files or metadata yaml files.