doc: fix json generator warnings

- Fix `console.countReset()` signature
- Fix `console.group()` arguments list

PR-URL: https://github.com/nodejs/node/pull/16742
Reviewed-By: Anatoli Papirovski <apapirovski@mac.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Daniel Bevenius <daniel.bevenius@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

doc/api/console.md

@@ -216,7 +216,7 @@ undefined
 >
 ```
 
-### console.countReset([label = 'default'])
+### console.countReset([label='default'])
 <!-- YAML
 added: v8.3.0
 -->
@@ -293,7 +293,7 @@ values are concatenated. See [`util.format()`][] for more information.
 added: v8.5.0
 -->
 
-* `label` {any}
+* `...label` {any}
 
 Increases indentation of subsequent lines by two spaces.