Reduce serial hook binary footprint.

[X-Ryl669]

Description

Reduce the binary size of my serial hooking code, as spotted by @thinkyhead .
Without this PR, I had:

Advanced Memory Usage is available via "PlatformIO Home > Project Inspect"
RAM:   [========= ]  88.9% (used 58248 bytes from 65536 bytes)
Flash: [========= ]  86.9% (used 455740 bytes from 524288 bytes)
encrypt([".pio/build/mks_robin_nano35/debug/firmware.bin"], [".pio/build/mks_robin_nano35/debug/firmware.elf"])

After the PR, I now have:

Advanced Memory Usage is available via "PlatformIO Home > Project Inspect"
RAM:   [========= ]  88.9% (used 58248 bytes from 65536 bytes)
Flash: [========= ]  86.1% (used 451500 bytes from 524288 bytes)
encrypt([".pio/build/mks_robin_nano35/debug/firmware.bin"], [".pio/build/mks_robin_nano35/debug/firmware.elf"])

It also fix RuntimeHook connected call loop

Requirements

None

Benefits

Reduce binary flash size by 4.2kB on my system at the cost of a bit less inlining of the serial code's print and write functions.

Configurations

None

Related Issues

PR #20783 last comment from Scott.

[thinkyhead]

I agree that optimizing to code for size is much more valuable than optimizing for some miniscule performance gain in an area that's not a performance bottleneck (such as serial output).