Unknown printf() specifiers

[Dennisbonke]

While testing the coreutils programs the following utilities required an unimplemented printf() specifier ('76')

• seq
• dd

The following program required the unimplemented printf() specifier ('39'), which converts to an '

• xz

Furthermore, it seems we are lacking an implementation of %f

[Dennisbonke]

Converting 76 to ascii yields L, which seems to be an specifier for a long double conversion. This has been implemented in the meantime.

[Geertiebear]

Support for ' has been added as of https://github.com/managarm/frigg/commit/070aadc38552f226c64a015f050618a48918584f