added emit to ouput of bwa_index.nf

structuralvariants/nextflow/modules/bwa_index.nf

 process BWA_INDEX {
-  tag "bwa index"
+  tag { "bwa index" }
   container 'quay.io/biocontainers/bwa:0.7.17--h84994c4_5'
 
   input:
     path input
 
   output:
-    path "*.{amb,ann,bwt,pac,sa}"
-    
+    path "*.{amb,ann,bwt,pac,sa}", emit: indexs
+
   script:
   def algoType = params.algoType ? "-a $params.algoType" : ""
   """
   bwa index $algoType $input
   """
-}
\ No newline at end of file
+}