lang/mecrisp-stellaris: update to 2.6.2

Upstream changes:

• Fixed outsized binary for STM32G031F4
• Fixed :noname for RA in loadable ansification layer
• Contribution by Jan Bramkamp: Bit field tools Improved PLL initialisation code for STM32F411
• Contribution by Gareth Edwards New target: Black pill with STM32F401CC Bugfix for flash size and comments for STM32F401CD target
• Contribution by Peter Jakacki: Tachyon extensions for RP2040

PR: 262463