fix [FUN-L-*] typo
Under C.2.1 List of risk factors, \[FUN\] Sensitivity of functions, the level references are currently \[SDT-L-0\], \[SDT-L-1\], and \[SDT-L-2\].
This is probably a copy paste error. They should be \[FUN-L-0\], \[FUN-L-1\], \[FUN-L-2\].
issue