use a generic linked list (#3487)

internal/utils/linkedlist/README.md

@@ -1,11 +1,4 @@
 # Usage
 
 This is the Go standard library implementation of a linked list 
-(https://golang.org/src/container/list/list.go), modified such that genny
-(https://github.com/cheekybits/genny) can be used to generate a typed linked
-list.
-
-To generate, run
-```
-genny -pkg $PACKAGE -in linkedlist.go -out $OUTFILE gen Item=$TYPE
-```
+(https://golang.org/src/container/list/list.go), modified to use Go generics.