I assume that the people doing this are posting from mobile, so they researched something, collected the link, and used it. Probably they don't even notice that the link is sub-optimal, so thanks for raising awareness.
If authors can edit those links that's great, but if they don't, anybody else should feel free to edit in this change. That way only the ...
The formatting is MathJax and is pretty useful for complex math. If you want to use a normal dollar sign you have to "escape" the symbol. This means that you tell the interpreter "You know, the following is just a normal character. Not some formatting stuff like 'I want this italic', or 'I want this bold' or 'I want this in fancy math-whatever style'".
This sounds like something that Stack Exchange’s automatical link conversion could automatically do, given that Wikipedia is probably the most linked external source. It’s not much different from converting this:
Please don't link to m.wikipedia.org
I now posted a feature request for this ...
No such specific guidelines exist on this site, though the community here tends to reject 'cosmetic' edits unless they are substantive and/or drastically increase the quality of the question/answer.
In the odd case where edits have been disagreed over and one or both parties are unsatisfied with the result they have brought the question here to ask the ...
This is a topic I feel quite strongly about. I personally use MathJax a lot, in particular for quantities. I find that it:
Visually distinguishes them from the surrounding text, so that a reader can skim quickly through my answer without missing anything. My reasoning for this is that I usually emphasize the calculation: for me, the important information ...
Could it be a case of
I think the problem is not that it should be followed by white space (this works) but it cannot be preceeded by non-alphanum character (you see the **stars **).
There are no specific guidelines, but I'll give my opinion on cosmetic edits.
People use the close reason unclear what you're asking for certain reasons but to me a question can be unclear because of how badly formatted the question is.
Zero line breaks, superfluous whitespace, unnecessary phrases such as salutations or apologies (such as for perceived sub-...
I had to hunt around to find how to use units. If it were explained on a cheetnsheet summary...? What I found was a different word, though.
Another "minor" use that could be handled without TeX is superscrips. It's not on the toolbar or markdown, but html tags work. I've seen posts use mathjax to get the superscript but then mess up the unit.