Remove unused receivers (#1685)

* remove unsed receiver

* fix

* fix

Author: KAZYPinkSaurus

docs/sources/k6/next/extensions/create/output-extensions.md

@@ -133,7 +133,7 @@ func (*Logger) Description() string {
 
 // Start initializes any state needed for the output, establishes network
 // connections, etc.
-func (o *Logger) Start() error {
+func (*Logger) Start() error {
     return nil
 }
 

docs/sources/k6/v0.57.x/extensions/create/output-extensions.md

@@ -133,7 +133,7 @@ func (*Logger) Description() string {
 
 // Start initializes any state needed for the output, establishes network
 // connections, etc.
-func (o *Logger) Start() error {
+func (*Logger) Start() error {
     return nil
 }