go-staticcheck fixes

Nothing significant and all manually tested, these are the recommended
fixes from staticcheck.

helpers.go

@@ -222,11 +222,7 @@ func (p *Policy) AllowDataURIImages() {
 			}
 
 			_, err := base64.StdEncoding.DecodeString(url.Opaque[len(matched):])
-			if err != nil {
-				return false
-			}
-
-			return true
+			return err == nil
 		},
 	)
 }

sanitize.go

@@ -95,41 +95,6 @@ func (p *Policy) SanitizeReaderToWriter(r io.Reader, w io.Writer) error {
 	return p.sanitize(r, w)
 }
 
-const escapedURLChars = "'<>\"\r"
-
-func escapeUrlComponent(w stringWriterWriter, val string) error {
-	i := strings.IndexAny(val, escapedURLChars)
-	for i != -1 {
-		if _, err := w.WriteString(val[:i]); err != nil {
-			return err
-		}
-		var esc string
-		switch val[i] {
-		case '\'':
-			// "&#39;" is shorter than "&apos;" and apos was not in HTML until HTML5.
-			esc = "&#39;"
-		case '<':
-			esc = "&lt;"
-		case '>':
-			esc = "&gt;"
-		case '"':
-			// "&#34;" is shorter than "&quot;".
-			esc = "&#34;"
-		case '\r':
-			esc = "&#13;"
-		default:
-			panic("unrecognized escape character")
-		}
-		val = val[i+1:]
-		if _, err := w.WriteString(esc); err != nil {
-			return err
-		}
-		i = strings.IndexAny(val, escapedURLChars)
-	}
-	_, err := w.WriteString(val)
-	return err
-}
-
 // Query represents a single part of the query string, a query param
 type Query struct {
 	Key      string
@@ -994,7 +959,7 @@ func (p *Policy) validURL(rawurl string) (string, bool) {
 			}
 
 			for _, urlPolicy := range urlPolicies {
-				if urlPolicy(u) == true {
+				if urlPolicy(u) {
 					return u.String(), true
 				}
 			}

sanitize_test.go

@@ -49,7 +49,7 @@ type test struct {
 func TestEmpty(t *testing.T) {
 	p := StrictPolicy()
 
-	if "" != p.Sanitize(``) {
+	if p.Sanitize(``) != `` {
 		t.Error("Empty string is not empty")
 	}
 }
@@ -459,10 +459,7 @@ func TestGlobalURLPatternsViaCustomPolicy(t *testing.T) {
 		"https",
 		func(url *url.URL) bool {
 			// Allow YouTube
-			if url.Host == `www.youtube.com` {
-				return true
-			}
-			return false
+			return url.Host == `www.youtube.com`
 		},
 	)