wikipedia: skip messagebox template contents

[dgw]

Description

It took me literally ten minutes to write and test this, albeit not that thoroughly. Should fix #2158, though the reason I opened that issue is I thought it would take more effort/time…

Demo

<Sopel 7.1.2> [wikipedia] Gurmukhi - Letters | "This article contains IPA phonetic symbols. Without proper
              rendering support, you may see question marks, boxes, or other symbols instead of Unicode
              characters. For an introductory guide on IPA symbols, see Help:IPA. The Gurmukhī alphabet contains
              thirty-five base letters (akkhara, plural akkharā̃), traditionally arranged in seven rows of five
              letters each. The first three letters, or mātarā vāhak ("vowel carrier"), […]"
<This PR> [wikipedia] Gurmukhi - Letters | "The Gurmukhī alphabet contains thirty-five base letters (akkhara,
          plural akkharā̃), traditionally arranged in seven rows of five letters each. The first three letters, or
          mātarā vāhak ("vowel carrier"), are distinct because they form the basis for vowels and are not
          consonants, or vianjan, like the remaining letters are, and except for the second letter aiṛā are never
          used on their own; see § […]"

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

[Exirel]

Looks good.