Add --preserve-quotes to yamlfmt in pre-commit check

[james-ball-qualcomm]

Now that I'm about to put a test normative rules definition YAML file in this repo, we'll need the same fix applied as we did in the ISA manual:
PR: riscv/riscv-isa-manual#2268
Issue: riscv/riscv-isa-manual#2267

@wmat, adding you here so you are in the loop.

This needs to happen before my PR to add norm rule tests can proceed (see this failure https://github.com/riscv/docs-resources/actions/runs/17745093666/job/50428352635?pr=74)

Rafael, can you make this change? You are much less likely to screw it up than me :-)

[james-ball-qualcomm]

@rpsene, will you be able to fix this for me?