templates: HasPrefix support for template.HTML

Refactor locale&string&template related code has .Title be
template.HTML and "Improve HTML title on repositories" needs to check
the prefix with StringUtils.HasPrefix

modules/templates/util_string.go

@@ -4,6 +4,7 @@
 package templates
 
 import (
+	"html/template"
 	"strings"
 
 	"code.gitea.io/gitea/modules/base"
@@ -17,8 +18,14 @@ func NewStringUtils() *StringUtils {
 	return &stringUtils
 }
 
-func (su *StringUtils) HasPrefix(s, prefix string) bool {
-	return strings.HasPrefix(s, prefix)
+func (su *StringUtils) HasPrefix(s any, prefix string) bool {
+	switch v := s.(type) {
+	case string:
+		return strings.HasPrefix(v, prefix)
+	case template.HTML:
+		return strings.HasPrefix(string(v), prefix)
+	}
+	return false
 }
 
 func (su *StringUtils) Contains(s, substr string) bool {

modules/templates/util_string_test.go

@@ -0,0 +1,20 @@
+// Copyright Earl Warren <contact@earl-warren.org>
+// SPDX-License-Identifier: MIT
+
+package templates
+
+import (
+	"html/template"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_StringUtils_HasPrefix(t *testing.T) {
+	su := &StringUtils{}
+	assert.True(t, su.HasPrefix("ABC", "A"))
+	assert.False(t, su.HasPrefix("ABC", "B"))
+	assert.True(t, su.HasPrefix(template.HTML("ABC"), "A"))
+	assert.False(t, su.HasPrefix(template.HTML("ABC"), "B"))
+	assert.False(t, su.HasPrefix(123, "B"))
+}