Update Go versions and testing logic in Github actions

The .github/workflows/test.yaml file has been updated to include Go 1.21.x in testing. Additionally, the superscript_test.go and subscript_test.go testing logic has been refactored.

.github/workflows/test.yaml

@@ -5,7 +5,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        go-version: [1.19.x, 1.20.x]
+        go-version: [1.19.x, 1.20.x, 1.21.x]
         platform: [ubuntu-latest, macos-latest, windows-latest]
     runs-on: ${{ matrix.platform }}
     steps:

subscript_test.go

@@ -5,17 +5,13 @@ import (
 	"testing"
 
 	"github.com/yuin/goldmark"
-	"github.com/yuin/goldmark/renderer/html"
 	"github.com/yuin/goldmark/testutil"
 )
 
 func TestSubscript(t *testing.T) {
 	markdown := goldmark.New(
-		goldmark.WithRendererOptions(
-			html.WithUnsafe(),
-		),
 		goldmark.WithExtensions(
-			Subscript,
+			Subscript, Superscript,
 			extension.Strikethrough,
 		),
 	)

superscript_test.go

@@ -4,17 +4,13 @@ import (
 	"testing"
 
 	"github.com/yuin/goldmark"
-	"github.com/yuin/goldmark/renderer/html"
 	"github.com/yuin/goldmark/testutil"
 )
 
 func TestSuperscript(t *testing.T) {
 	markdown := goldmark.New(
-		goldmark.WithRendererOptions(
-			html.WithUnsafe(),
-		),
 		goldmark.WithExtensions(
-			Superscript,
+			Superscript, Subscript,
 		),
 	)
 	testutil.DoTestCaseFile(markdown, "_test/superscript.txt", t, testutil.ParseCliCaseArg()...)