Improve code block comparison

I added line numbers and line highlights to make it easier to
realise which lines changed from "Before" to "After". When testing
the training, sometimes it wasn't so straightforward to see what
changed and line numbers are very useful when teaching.

Author: mribeirodantas

docs/side_quests/nf-test.md

@@ -326,7 +326,7 @@ You may be wondering how we're going to point to the root of the pipeline in the
 
 _Before:_
 
-```groovy title="tests/main.nf.test"
+```groovy title="tests/main.nf.test" linenums="1" hl_lines="3 4"
 when {
     params {
         // define parameters here. Example:
@@ -337,7 +337,7 @@ when {
 
 _After:_
 
-```groovy title="tests/main.nf.test"
+```groovy title="tests/main.nf.test" linenums="1" hl_lines="3"
 when {
     params {
         input_file = "${projectDir}/greetings.csv"
@@ -409,7 +409,7 @@ Let's add an assertion to our test to check the pipeline runs the expected numbe
 
 **Before:**
 
-```groovy title="tests/main.nf.test"
+```groovy title="tests/main.nf.test" linenums="1" hl_lines="1 11"
     test("Should run without failures") {
 
         when {
@@ -427,7 +427,7 @@ Let's add an assertion to our test to check the pipeline runs the expected numbe
 
 **After:**
 
-```groovy title="tests/main.nf.test"
+```groovy title="tests/main.nf.test" linenums="1" hl_lines="1 11"
     test("Should run successfully with correct number of processes") {
 
         when {
@@ -474,7 +474,7 @@ Let's add an assertion to our test to check the output file was created. We'll a
 
 **Before:**
 
-```groovy title="tests/main.nf.test"
+```groovy title="tests/main.nf.test" linenums="1" hl_lines="14"
     test("Should run successfully with correct number of processes") {
 
         when {
@@ -493,7 +493,7 @@ Let's add an assertion to our test to check the output file was created. We'll a
 
 **After:**
 
-```groovy title="tests/main.nf.test"
+```groovy title="tests/main.nf.test" linenums="1" hl_lines="14-33"
     test("Should run successfully with correct number of processes") {
 
         when {
@@ -667,7 +667,7 @@ The test fails because the `sayHello` process declares 1 input channel but 0 wer
 
 **Before:**
 
-```groovy title="tests/main.sayhello.nf.test"
+```groovy title="tests/main.sayhello.nf.test" linenums="1" hl_lines="1 10 11"
     test("Should run without failures") {
 
         when {
@@ -693,7 +693,7 @@ The test fails because the `sayHello` process declares 1 input channel but 0 wer
 
 **After:**
 
-```groovy title="tests/main.sayhello.nf.test"
+```groovy title="tests/main.sayhello.nf.test" linenums="1" hl_lines="1 10"
     test("Should run without failures and produce correct output") {
 
         when {
@@ -806,10 +806,8 @@ Here's how we could modify our test to check specific content:
 
 **Before:**
 
-```groovy title="tests/main.sayhello.nf.test"
-process {
-    """
-        test("Should run without failures and produce correct output") {
+```groovy title="tests/main.sayhello.nf.test" linenums="1" hl_lines="1 5 6 17"
+    test("Should run without failures and produce correct output") {
 
         when {
             params {
@@ -829,15 +827,13 @@ process {
         }
 
     }
-
-    """
-}
 ```
 
 **After:**
 
-```groovy title="tests/main.sayhello.nf.test"
+```groovy title="tests/main.sayhello.nf.test" linenums="1" hl_lines="1 5 16 17"
      test("Should run without failures and contain expected greeting") {
+
         when {
             params {
                 // define parameters here
@@ -854,6 +850,7 @@ process {
             assert path(process.out[0][0]).readLines().contains('hello')
             assert !path(process.out[0][0]).readLines().contains('HELLO')
         }
+
     }
 ```
 
@@ -936,7 +933,7 @@ For now, let's re-use the existing data/greetings.csv file using the example we
 
 **Before:**
 
-```groovy title="tests/main.converttoupper.nf.test"
+```groovy title="tests/main.converttoupper.nf.test" linenums="1" hl_lines="1 10 11"
     test("Should run without failures") {
 
         when {
@@ -962,7 +959,7 @@ For now, let's re-use the existing data/greetings.csv file using the example we
 
 **After:**
 
-```groovy title="tests/main.converttoupper.nf.test"
+```groovy title="tests/main.converttoupper.nf.test" linenums="1" hl_lines="1 10"
     test("Should run without failures and produce correct output") {
 
         when {