What follows here are my personal considerations; I don't mean to say that everybody needs to do like I do.
In my posts I follow the punctuation I normally use when writing in English, which means I follow the punctuation rules used in American English.
When I am referring to an internal path, I normally quote it, as in "admin/config/modules." As I follow the American rules for the punctuation, it can happen the punctuation for the sentence is included in the quoted path, which what happens if there is a comma, or a period; the semicolon would not be included in the quoted part.
My alternative to avoid causing misunderstanding about which exactly is the internal path is writing it in italic, such as admin/config/modules. In this case, the punctuation of the sentence would be external to the internal path.
This is not different from what normally done in American English where you can see sentences similar to the following ones:
Since is used with three different meanings.
The NOAD reports a note about the usage of "since."
Considering that is an internal path, I think it would be evident it is an internal path, even if it is left unquoted, and the Markdown parser doesn't differentiate it from the other text. If you want to make it stand out, you could write it as qualified path, such as http://example.com/admin/config/modules, where example.com is the usual domain used in example URLs that don't point to a precise/existing domain; in this way, the Markdown parser would handle it as a URL.
About the other alternatives you report, I have the following notes:
- I would not write the internal path as
admin/config/modules because that is what I do with code, or for something that I don't want it gets interpreted differently, or escaped, from the Markdown parser, such as "
<em>" that differently would be rendered as "'' or ". (The tag has been used to highlight the text in bold, in the last part of the sentence.)
- I would highlight the internal path only if I want the OP notices there is a typo in the reported internal path, and that is relevant for the question (e.g. that is the reason the OP is not able to do something). I barely highlight words in bold when writing in English, and that is what I do when posting on a Stack Exchange site.
- The difference between using double quote characters or single quote characters is, for what I can see, merely a different usage between American English, and British English. Both of them are equally valid.