.netlist syntax should support declaring "connection name"s in value field

Currently `.netlist` syntax require named connections to be defined in the `key` field: 

```ls
netlist:
  "gnd": "a.1 b.2"
  "5v": "a.2 k.5"
  1: "c.2 5v"
```

It must support the following variations:

```ls
netlist:
  "gnd": "a.1 b.2"
  1: "c.2 5v a.2"
  "k.5": "5v"
```