Fixing incorrect cell names in device documentation

[glatosinski]

Fixes #163

This PR fixes error cell names in device details section of the documentation.

[glatosinski]

After looking at the documentation and the libraries/ directory there are several inconsistencies that I'm not sure how to solve:

• sky130_fd_pr__cap_min_m4 does not seem to exist in libraries/,
• sky130_fd_pr__esd_nfet_g5v0d10v5_nvt does not seem to exist,
• sky130_fd_pr__nfet_extenddrain and sky130_fd_pr__pfet_extenddrain don't exist in libraries/ - those cell names occur for nfet_20v0_zvt, nfet_20v0, nfet_20v0_iso, nfet_20v0_nvt, nfet_g11v0d16v0, pfet_g5v0d16v0 and pfet_20v0

[mithro]

I /think/ this LGTM.

However, it does make me wonder what we mean by Cell Name: and Model Name here?

[diadatp]

Has the intention behind Cell Name and Model Name been clarified?
Some of the devices have an associated fixed layout in sky130_fd_pr/cells/ while others only have models. Does that have something to do with it?

Some of the other issues:

• The generic resistors section does not mention a Cell Name but does specify a "type" and "model".
• The bipolar (PNP) section mentions the same model (sky130_fd_pr__pnp_05v5) twice whereas the only models available are the subcircuits sky130_fd_pr__pnp_05v5_W3p40L3p40 and sky130_fd_pr__pnp_05v5_W0p68L0p68.
• There is a mismatch between the models mentioned in the docs and those available in sky130_fd_pr. For example in the case of the MIM capacitors, the mentioned models sky130_fd_pr__model__cap_mim and sky130_fd_pr__cap_mim_m4 do not exist. Instead, sky130_fd_pr__model__cap_mim is part of the name of the file (sky130_fd_pr/models/capacitors/sky130_fd_pr__model__cap_mim.model.spice) that imports the required models and as noted previously, sky130_fd_pr__cap_mim_m4 does not occur anywhere. The correct models are the subcircuits sky130_fd_pr__cap_mim_m3_1 and sky130_fd_pr__cap_mim_m3_2. In this case the cell model distinction makes some sense.