text: Title: Parsing model: `Documentation.from_params(...).value` doesn't work
  Body: Documentation.from_params(...) has problems with multiline values and empty lines.
  
  Must be investigated more closely and there must be more tests about this.
  
  https://github.com/robotframework/robotframework/blob/c80464b98f1efff1d966865eddec6120cf95ad18/src/robot/parsing/model/statements.py#L166
  
  Revert this commit 0c5d7f1fcac4ef9bd0178df27528e985af7dafb6 from "custom parsers" #4614 because it should be fixed independently.