Wording in some conf.d/ files

The following message can be found in some configuration files and needs fixing:

    This configuration is available on the major desktop environments.
    We shouldn't overwrite it with "assign" unconditionally.
    Most clients may picks up the first value only. so using "append"
    may simply works to avoid it.

I'm not well versed in fontconfig and don't want to skew the intended meaning, hence a GitLab issue rather than a PR.

The 3rd/4th sentences (they should be 1 sentence) give me an ambiguous feeling. Since We shouldn't overwrite urges caution, it looks like may simply works to avoid it is supposed to convey “may prevent it”, despite being written like something the user wants.

The following files contain the message:

conf.d/09-autohint-if-no-hinting.conf
conf.d/10-autohint.conf
conf.d/10-hinting-full.conf
conf.d/10-hinting-medium.conf
conf.d/10-hinting-none.conf
conf.d/10-hinting-slight.conf
conf.d/10-no-sub-pixel.conf
conf.d/10-sub-pixel-bgr.conf
conf.d/10-sub-pixel-rgb.conf
conf.d/10-sub-pixel-vbgr.conf
conf.d/10-sub-pixel-vrgb.conf
conf.d/10-unhinted.conf
conf.d/11-lcdfilter-default.conf
conf.d/11-lcdfilter-legacy.conf
conf.d/11-lcdfilter-light.conf