Function register

register(...args: any[]): object | Function
Register an extension Group that subsequently registers extensions.
Parameters
- ...args: any[]
  Optional name followed by a Group class, instance, or function.
Returns object | Function
the registered group.
Example
```
Extensions.register(UmlExtensions)
Extensions.register('uml', UmlExtensions)
Extensions.register(function () { this.blockMacro('plantuml', PlantUmlBlock) })
Extensions.register('uml', function () { this.blockMacro('plantuml', PlantUmlBlock) })
```
- Defined in extensions.d.ts:731