Update output.md

Author: MatthiasZepper

docs/output.md

@@ -94,6 +94,8 @@ If multiple libraries/runs have been provided for the same sample in the input s
 
 [UMI-tools](https://github.com/CGATOxford/UMI-tools) deduplicates reads based on unique molecular identifiers (UMIs) to address PCR-bias. Firstly, the UMI-tools `extract` command removes the UMI barcode information from the read sequence and adds it to the read name. Secondly, reads are deduplicated based on UMI identifier after mapping as highlighted in the [UMI-tools dedup](#umi-tools-dedup) section.
 
+To facilitate processing of input data which has the UMI barcode already embedded in the read name from the start, `--skip_umi_extract` can be specified in conjunction with `--with_umi`.
+
 ### TrimGalore
 
 <details markdown="1">