Key-identifier option support

[EmergReanimator]

Hi,

It would be great if key-identifier option could be supported by CMSIS configuration wizard

Version 2.6.0 seems to be lack of that feature.

https://www.keil.com/pack/doc/CMSIS/Pack/html/configWizard.html#configWizard_annotations

Option with identifier selection replacing the identifier after the specified key-identifier:

//   <o TIMESTAMP_SRC>Time Stamp Source
//      <dwt=>     DWT Cycle Counter
//      <systick=> SysTick
//      <user=>    User Timer 
//   <i>Selects source for 32-bit time stamp
#define TIMESTAMP_SRC  dwt