fix trailing slash that breaks link

episodes/03-ncbi-sra.md

@@ -25,7 +25,7 @@ There are many repositories for public data. Some model organisms or fields have
 
 ## Accessing the original archived data
 
-The [sequencing dataset (from Tenaillon, *et al.* 2016) adapted for this lesson](https://www.datacarpentry.org/organization-genomics/data/) was obtained from the [NCBI Sequence Read Archive](https://www.ncbi.nlm.nih.gov/sra), which is a large (~27 petabasepairs/2.7 x 10^16 basepairs as of April 2019) repository for next-generation sequence data. Like many NCBI databases, it is complex and mastering its use is greater than the scope of this lesson. Very often there will be a direct link (perhaps in the supplemental information) to where the SRA dataset can be found. We are only using a small part of these data, so a direct link cannot be found. If you have time, go through the following detailed description of finding the data we are using today (otherwise skip to the next section).
+The [sequencing dataset (from Tenaillon, *et al.* 2016) adapted for this lesson](https://www.datacarpentry.org/organization-genomics/data) was obtained from the [NCBI Sequence Read Archive](https://www.ncbi.nlm.nih.gov/sra), which is a large (~27 petabasepairs/2.7 x 10^16 basepairs as of April 2019) repository for next-generation sequence data. Like many NCBI databases, it is complex and mastering its use is greater than the scope of this lesson. Very often there will be a direct link (perhaps in the supplemental information) to where the SRA dataset can be found. We are only using a small part of these data, so a direct link cannot be found. If you have time, go through the following detailed description of finding the data we are using today (otherwise skip to the next section).
 
 ### Locate the Run Selector Table for the Lenski Dataset on the SRA