Lef lexer issues with semi-numeric values

[nanobowers]

The LEF lexer currently doesn't like the following numeric looking values:

• Floats with exponents, e.g: EDGECAPACITANCE 40.567E-6 ;
• Strings with leading numbers, e.g.: SITE 18T
  • ... Afaict the 18 is slurped as a number token and then there is a string token following

the referenced publicly available LEF: https://github.com/idea-fasoc/OpenFASOC/blob/c11ceb17997648a975f99738a8890a2288143e08/openfasoc/common/platforms/sky130osu18Ths/lef/sky130_osu_sc_18T_hs.tlef