DVT SystemVerilog IDE User Guide
Rev. 19.1.50, 7 February 2020
You can easily merge the 'extern' prototype of a method with its out-of-block implementation.
Place the editor cursor either on the method's prototype or on the implementation and press Ctrl+1, select Join extern ... prototype and implementation from the list of quick assist proposals and press Enter.
The implementation is joined with the prototype:
Tip: You can also right-click in the editor and go to Refactor > Join extern and implementation.