wikipedia: use say() instead of reply() when reporting a URL error

[SnoopJ]

Description

This PR removes user highlights bot.reply() from the wikipedia plugin, in favor of the non-highlighting bot.say()

Note: this PR is motivated by a personal opinion about netiquette; a user sharing a Wikipedia URL may not even know the Sopel instance exists, and the bot highlighting them is the kind of thing I consider a bit of an aggravation. Feel free to close this PR on that basis 😅

Existing behavior

16:33 <SnoopJ> https://en.wikipedia.org/wiki/Diffraction_spike#/media/File:Comparison_strut_diffraction_spikes.svg
16:33 <terribot> SnoopJ: Error fetching section "/media/File:Comparison_strut_diffraction_spikes.svg" for page "Diffraction spike".

Behavior with this patch

16:34 <SnoopJ> https://en.wikipedia.org/wiki/Diffraction_spike#/media/File:Comparison_strut_diffraction_spikes.svg
16:34 <terribot> [wikipedia] Error fetching section "/media/File:Comparison_strut_diffraction_spikes.svg" for page "Diffraction spike".

Checklist

• I have read CONTRIBUTING.md
• I can and do license this contribution under the EFLv2
• No issues are reported by make qa (runs make quality and make test)
• I have tested the functionality of the things this change touches

[dgw]

I think IRC discussion yesterday established that this is desirable for URL-triggered calls only. A command that results in an error should still reply().

See the xkcd and reddit plugins for examples of other core plugins that respond differently depending on trigger type. (reddit, in particular, simply doesn't respond if e.g. an inline u/name reference points to an invalid entity.)

[dgw]

This is good to squash down, IMO. Note our commit message convention, which would go something like this for this PR:

wikipedia: use say() instead of reply() when reporting a URL error

[dgw]

No one told you I prefer not to actually rebase onto master during squash if possible, because it makes verifying that the PR contains no extra changes easier, but this patch is small enough that it's nbd.