fix: linter errors (#263)

* refactor: extract magic numbers to const

* fix: linter errors

ansi/blockstack.go

@@ -57,7 +57,7 @@ func (s BlockStack) Margin() uint {
 	return i
 }
 
-// Width returns the available rendering width
+// Width returns the available rendering width.
 func (s BlockStack) Width(ctx RenderContext) uint {
 	if s.Indent()+s.Margin()*2 > uint(ctx.options.WordWrap) {
 		return 0

ansi/heading.go

@@ -14,22 +14,31 @@ type HeadingElement struct {
 	First bool
 }
 
+const (
+	h1 = iota + 1
+	h2
+	h3
+	h4
+	h5
+	h6
+)
+
 func (e *HeadingElement) Render(w io.Writer, ctx RenderContext) error {
 	bs := ctx.blockStack
 	rules := ctx.options.Styles.Heading
 
 	switch e.Level {
-	case 1:
+	case h1:
 		rules = cascadeStyles(true, rules, ctx.options.Styles.H1)
-	case 2:
+	case h2:
 		rules = cascadeStyles(true, rules, ctx.options.Styles.H2)
-	case 3:
+	case h3:
 		rules = cascadeStyles(true, rules, ctx.options.Styles.H3)
-	case 4:
+	case h4:
 		rules = cascadeStyles(true, rules, ctx.options.Styles.H4)
-	case 5:
+	case h5:
 		rules = cascadeStyles(true, rules, ctx.options.Styles.H5)
-	case 6:
+	case h6:
 		rules = cascadeStyles(true, rules, ctx.options.Styles.H6)
 	}
 

ansi/image.go

@@ -9,7 +9,7 @@ type ImageElement struct {
 	Text    string
 	BaseURL string
 	URL     string
-	Child   ElementRenderer // FIXME
+	Child   ElementRenderer
 }
 
 func (e *ImageElement) Render(w io.Writer, ctx RenderContext) error {

ansi/link.go

@@ -10,7 +10,7 @@ type LinkElement struct {
 	Text    string
 	BaseURL string
 	URL     string
-	Child   ElementRenderer // FIXME
+	Child   ElementRenderer
 }
 
 func (e *LinkElement) Render(w io.Writer, ctx RenderContext) error {

ansi/templatehelper.go

@@ -6,7 +6,7 @@ import (
 	"text/template"
 )
 
-// TemplateFuncMap contains a few useful template helpers
+// TemplateFuncMap contains a few useful template helpers.
 var (
 	TemplateFuncMap = template.FuncMap{
 		"Left": func(values ...interface{}) string {