add zener, fix some other diodes

[LHSmicius]

Add zener symbol and base zener part on SOT-23. Created only base zener diode, because there are so many of them (including those zener voltage differences), so I use base parts in my projects and change "Custom value" field.
Reference: https://assets.nexperia.com/documents/data-sheet/BZX84_SER.pdf

Also fix some minor mistakes on other diodes.

[LHSmicius]

Bot!

[RX14]

IEC 60617 shows

might be good to change the symbol to match that. Also keep in mind that your text placement isn't quite right for all the different orientations.

[LHSmicius]

Bot!
Nice to see you back, Stephanie!

[github-actions]

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Items in this PR

State	Type	Name	Checks	Version	Filename
Modified	Entity	Diode	✔️ Pass	0 ✔️	entities/diode/diode.json
Modified	Entity	Schottky diode	✔️ Pass	0 ✔️	entities/diode/schottky_diode.json
New	Entity	Zener diode	✔️ Pass	0 ✔️	entities/diode/zener_diode.json
New	Part	base SOD-123 schottky diode	✔️ Pass	0 ✔️	parts/diode/schottky/base-sod-123.json
New	Part	base SOT-23 zener diode	✔️ Pass	1 ✔️	parts/diode/zener/base-sot-23.json
New	Symbol	Zener diode	✔️ Pass	1 ✔️	symbols/diode/zener_diode.json
New	Unit	Zener diode	✔️ Pass	0 ✔️	units/diode/zener_diode.json

Non-items

• parts/diode/base-sod-123.json

Non-new files

Status	File
Modified	entities/diode/diode.json
Modified	entities/diode/schottky_diode.json
Deleted	parts/diode/base-sod-123.json

Parts overview (excluding derived)

Bold items are from this PR

• Part base SOT-23 zener diode
  • Package SOT-23
    • Padstack SMD rectangular with rounded corners
    • 3D Model 3d_models/ic/so/SOT-23.step
  • Entity Zener diode
    • Unit Zener diode
      • Symbol Zener diode
• Part base SOD-123 schottky diode
  • Package SOD-123
    • Padstack SMD rectangular
    • 3D Model 3d_models/diode/D_SOD-123.step
  • Entity Schottky diode
    • Unit Schottky diode
      • Symbol Schottky diode

Items not associated with any part

• Entity Diode

Details

Parts

base SOT-23 zener diode

✔️ Checks passed

Attribute	Value
MPN	base SOT-23 zener diode
Value
Manufacturer	(125 other parts)
Datasheet
Description	base zener diode, SOT-23
Tags	diode smd zener

Flags

• Base part

Pad	Gate	Pin
1	Main	A
2	-	-
3	Main	K

base SOD-123 schottky diode

✔️ Checks passed

Attribute	Value
MPN	base SOD-123 schottky diode
Value
Manufacturer	(125 other parts)
Datasheet
Description	base schottky diode, SOD-123
Tags	diode

Pad	Gate	Pin
1	Main	K
2	Main	A

MBR0520LT1G

Inerhits from base SOD-123 schottky diode

✔️ Checks passed

Attribute	Value
MPN	MBR0520LT1G
Value	(inherited)
Manufacturer	ON Semiconductor (14 other parts)
Datasheet	http://www.onsemi.com/pub/Collateral/MBR0520LT1-D.PDF
Description	Surface Mount Schottky Power Rectifier
Tags	diode schottky (inherited)

Entities

Diode

✔️ Checks passed

Attribute	Value
Manufacturer	(125 other parts)
Prefix	D
Tags	diode discrete generic

Gate	Suffix	Swap group	Unit
Main		0	Diode

Schottky diode

✔️ Checks passed

Attribute	Value
Manufacturer	(125 other parts)
Prefix	D
Tags	diode discrete generic

Gate	Suffix	Swap group	Unit
Main		0	Schottky diode

Zener diode

✔️ Checks passed

Attribute	Value
Manufacturer	(125 other parts)
Prefix	D
Tags	diode discrete generic

Gate	Suffix	Swap group	Unit
Main		0	Zener diode

Units

Zener diode

✔️ Checks passed

Attribute	Value
Manufacturer	(125 other parts)

Pin	Direction
A	Passive
K	Passive

Symbol: Zener diode

✔️ Checks passed

• Is box symbol

Angle	Normal	Mirrored
0°
90°
180°
270°