fix typo

docs/usage.md

@@ -93,7 +93,7 @@ CONTROL_REP1,AEG588A1_S1_L004_R1_001.fastq.gz
 
 The pipeline will auto-detect whether a sample is single- or paired-end using the information provided in the samplesheet. The samplesheet can have as many columns as you desire. However, there is a strict requirement for the first 3 columns to match those defined in the table below.
 
-A final samplesheet file consisting single-end data may look something like the one below. This is for 6 samples, where `TREATMENT_REP3` has been sequenced twice.
+A final samplesheet file consisting of single-end data and may look something like the one below. This is for 6 samples, where `TREATMENT_REP3` has been sequenced twice.
 
 ```console
 sample,fastq_1