made tutorial outputs more presentable (#555)

Closes https://github.com/ooni/probe/issues/1831

internal/tutorial/measurex/chapter11/README.md

@@ -95,13 +95,13 @@ here on `main` using the `PanicOnError` function.
 Let us perform a vanilla run first:
 
 ```bash
-go run -race ./internal/tutorial/measurex/chapter11
+go run -race ./internal/tutorial/measurex/chapter11 | jq
 ```
 
 Take a look at the JSON output and compare it with:
 
 ```bash
-go run -race ./internal/tutorial/measurex/chapter10 -url https://www.google.com
+go run -race ./internal/tutorial/measurex/chapter10 -url https://www.google.com | jq
 ```
 
 (which is basically forcing chapter10 to run with the
@@ -114,7 +114,7 @@ and compare it to the code written in chapter10?
 Now run:
 
 ```bash
-go run -race ./internal/tutorial/measurex/chapter11 -url https://google.com
+go run -race ./internal/tutorial/measurex/chapter11 -url https://google.com | jq
 ```
 
 Do you see the opportunity there for following redirections? :^).

internal/tutorial/measurex/chapter11/main.go

@@ -96,13 +96,13 @@ func main() {
 // Let us perform a vanilla run first:
 //
 // ```bash
-// go run -race ./internal/tutorial/measurex/chapter11
+// go run -race ./internal/tutorial/measurex/chapter11 | jq
 // ```
 //
 // Take a look at the JSON output and compare it with:
 //
 // ```bash
-// go run -race ./internal/tutorial/measurex/chapter10 -url https://www.google.com
+// go run -race ./internal/tutorial/measurex/chapter10 -url https://www.google.com | jq
 // ```
 //
 // (which is basically forcing chapter10 to run with the
@@ -115,7 +115,7 @@ func main() {
 // Now run:
 //
 // ```bash
-// go run -race ./internal/tutorial/measurex/chapter11 -url https://google.com
+// go run -race ./internal/tutorial/measurex/chapter11 -url https://google.com | jq
 // ```
 //
 // Do you see the opportunity there for following redirections? :^).