[DOC] Update description of RVFI tracer format in user manual

[silabs-oysteink]

The current version of the user manual describes the format from the tracer that used to be defined in cv32e40x_rvfi_trace.svh. This has been removed (PR #597) and instead the tracer in rvfi_sim_trace.sv is used.

The user manual should be updated to match the output format for this tracer.
The tracer file should also be renamed to cv32e40x_rvfi_trace.sv.
The user manual mentions CV32E40S_TRACE_EXECUTION / CV32E40X_TRACE_EXECUTION / trace_rvfi.log. These names should be removed and instead the three parameters of the rvfi_sim_trace module should be described.
The parameters should be connected to to be introduced parameters of cv32e40x/s_wrapper

[silabs-oysteink]

Should be good after PR #936