Fix the qualifier for the QUANT step and minor typo

The original input qualifier for index ("path") would only run one sample, changing it to "each" will run all samples when running the Nextflow file.

episodes/11-Simple_Rna-Seq_pipeline.md

@@ -489,7 +489,7 @@ The script `script4.nf`;
 process QUANT {
 
     input:
-    path index
+    each index
     tuple val(pair_id), path(reads)
 
     output:
@@ -731,7 +731,7 @@ ch1.collect().view()
 
 :::::::::::::::::::::::::::::::::::::::  challenge
 
-## Combing operators
+## Combining operators
 
 Which is the correct way to combined `mix` and `collect` operators so that you have a single channel with one List item?