Fix some small issues

Author: susannasiebert

02-prerequisites.Rmd

@@ -21,7 +21,7 @@ Docker is a tool that is used to automate the deployment of applications
 in lightweight containers so that applications can work efficiently in
 different environments in isolation. We provide versioned Docker containers
 for all pVACtools [releases](https://github.com/griffithlab/pVACtools/releases) 
-via [dockerhub griffithlab/pvactools](https://hub.docker.com/r/griffithlab/pvactools).
+via [Docker Hub using the griffithlab/pvactools image name](https://hub.docker.com/r/griffithlab/pvactools).
 
 In order to use Docker, you will to download the [Docker Desktop software](https://www.docker.com/get-started/).
 Please ensure you select the correct install package for your operating

03-running_pvactools.Rmd

@@ -159,7 +159,7 @@ Given the considerations outlined above, let's run pVACseq on our sample data.
 
 From the `optitype_normal_result.tsv` we know that the patient's class I alleles are
 HLA-A\*29:02, HLA-B\*45:01, HLA-B\*82:02, and HLA-C\*06:02 (indicated that two of three class I
-alleles are homozygous in this sample).We also have clinical typing information that confirms 
+alleles are homozygous in this sample). We also have clinical typing information that confirms 
 these class I alleles as well as identifying DQA1\*03:03, DQB1\*03:02, and DRB1\*04:05 as the 
 patient's class II alleles.