MCU_Microchip_PIC18, Regenerate with symgen, add alternate pin definitions

I have re-generated this library with symgen. Pin names with alternates separated by '/' have been converted to alternate pin definitions.

I'd like to get some feedback on how these symbols should be formatted consistently, e.g. for pins like ~MCLR, how should the alternates be ordered? When GPIO pins have an alternate OSCx function, should these be separated out or included with rest of GPIOs?

Graphical demonstration demo_MCU_Microchip_PIC18.pdf

There is a list of other inconsistencies to fix from #2098

• Name is wrong: PIC18LF45K50_QFP (should be -ML)
• MCLR-Pin position differs (top left, or in line with PortE, bottom left, ...)
• MCLR-Pin names differ
• VUSB not on top for most devices (PIC18F2450-IML)
• Pins not ordered in a sane manner (PIC18F24K50-xML)
• Symbol-Body to big (PIC18F24K50-xML)
• NC-Pins not on symbol outline (PIC18F4458-IML)

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