Cannot resolve documentationFileName for dokkaMultiModule

[fajarnuha]

Describe the bug
Cannot resolve documentationFileName for dokkaMultiModule

Expected behaviour
Should work as described in the official documentation

Screenshots
If applicable, add screenshots to help explain your problem

To Reproduce
just run as described

Dokka configuration
Configuration of dokka used to reproduce the bug

dokka { 
    outputFormat = 'html'
    ...
}

Installation

• Operating system: macOS/Windows/Linux
• Build tool: Gradle v5.6.4
• Dokka version: 1.4.10.2

Additional context
Add any other context about the problem here

[MarcinAman]

duplicate of #1530
Also the outputFormat property is no longer valid with new dokka (format is determined by a gradle command)