style: rename accessors to idiomatic names

internal/deezer/artist.go

@@ -18,11 +18,11 @@ type Artist struct {
 	} `json:"results"`
 }
 
-func (a *Artist) GetTitle() string {
+func (a *Artist) Title() string {
 	return a.Results.Data.Name
 }
 
-func (a *Artist) GetTracks() []*Track {
+func (a *Artist) Tracks() []*Track {
 	return a.Results.Tracks.Data
 }
 
@@ -30,11 +30,11 @@ func (a *Artist) SetTracks(t []*Track) {
 	a.Results.Tracks.Data = t
 }
 
-func (a *Artist) GetOutputDir(outputDir string) string {
+func (a *Artist) OutputDir(outputDir string) string {
 	base, _ := filenamify.Filenamify(a.Results.Data.Name, filenamify.Options{})
 	return path.Join(outputDir, base)
 }
 
-func (a *Artist) Unmarshal(data []byte) error {
+func (a *Artist) decode(data []byte) error {
 	return json.Unmarshal(data, a)
 }