Add ARM Keil Cx51 object record types to Omf51RecordTypes.java

[gtackett]

Is your feature request related to a problem? Please describe.
Ghidra 11.2 introduced the ability to perform some limited mark-up of Intel OMF-51 object file records.
ARM Keil's [henceforward, just Keil] toolchain for the Silicon Labs C8051Fxxx (C51/CX51 compilers, BL51 and LX51 linkers, and associated debuggers) introduce a number of new record types to those described in Intel's EXTERNAL PRODUCT SPECIFICATION
FOR THE MCS-51 OBJECT MODULE FORMAT V5.0 OMF-51 specification from 1982.

Several of the Keil-specific record types are essentially just slight modifications to record types defined by Intel.

Other record types added by Keil carry information that's used for features specific to Keil's extensions to the C language and for debugging.

As a first step toward more complete support for ARM Keil's added record types, symbolic names for each new type should be added to Omf51RecordTypes.java.

Describe the solution you'd like
I'll be pushing a change that will add symbols (using my own names) for the record types that I've partly or fully figured out.

Describe alternatives you've considered
No alternatives are apparent.