Added grid to plots

Signed-off-by: Grzegorz Latosinski <glatosinski@antmicro.com>

scripts/python-skywater-pdk/skywater_pdk/fet_simulator/fet_simulator.py

@@ -64,15 +64,19 @@ def init_plots():
     figs[0].suptitle('Id/W vs gm/Id')
     plts[0].set_xlabel("gm/Id")
     plts[0].set_ylabel("Id/W")
+    plts[0].grid(True)
     figs[1].suptitle('fT vs gm/Id')
     plts[1].set_xlabel("gm/Id")
     plts[1].set_ylabel("f_T")
+    plts[1].grid(True)
     figs[2].suptitle('gm/gds vs gm/Id')
     plts[2].set_xlabel("gm/Id")
     plts[2].set_ylabel("gm/gds")
+    plts[2].grid(True)
     figs[3].suptitle('gm/Id vs Vgg')
     plts[3].set_xlabel("Vgg")
     plts[3].set_ylabel("gm/Id")
+    plts[3].grid(True)
     return figs, plts