Fix ngspice netlisting when net names contain '/'

Fixes: lp:1821502
* https://bugs.launchpad.net/kicad/+bug/1821502

eeschema/netlist_exporters/netlist_exporter_pspice.cpp

@@ -150,6 +150,15 @@ bool NETLIST_EXPORTER_PSPICE::Format( OUTPUTFORMATTER* aFormatter, unsigned aCtl
                 // Replace parenthesis with underscore to prevent parse issues with simulators
                 ReplaceForbiddenChars( netName );
 
+                // Add quotes to nets containing slashes. This isn't added to ReplaceForbidenChars
+                // because this is only necessary for file writing; nets with slashes can be
+                // handled by ngspice after loading.
+                if( netName.Contains( "/" ) )
+                {
+                    netName.Prepend( '"' );
+                    netName.Append( '"' );
+                }
+
                 // Borrow LTSpice's nomenclature for unconnected nets
                 if( netName.IsEmpty() )
                     netName = wxString::Format( wxT( "NC_%.2u" ), NC_counter++ );