* do not run 'nix build' on arbitrary go src file changes, instead
(except for nix and flake related changes) only run on module-wide
changes, i.e. when sum,mod files change as these require flake
vendorSha256 updates or else they would fail to build.
* rm 'require_serial = false' occurences as that's the default value,
which makes it redundant here.
* do not "always_run" hooks
* only run relevant local hooks when pertaining files/file groups have
changed, e.g. there is no need to run statix linter when no nix files
have changed or equally it is not necessary to run 'nix build' when
none of the flake files (flake.{nix,lock}), any '*.nix' or go source,
mod or sum files have changed.
all of the above results in much faster pre-commit runs, i.e. shorter
feedback loops, i.e. faster iteration cycles.
