Miscellaneous doc formatting

* put all server arguments in backtick quotes, so they don't get turned into en-dashes
* `<code></code>` blocks on command line, so it stays in line with text

Also fixed some Python desired capabilities, and added one missed PHP sample.
> If it makes it unreadable on Github it's not particularly useful, no?

I agree, I'll make a note to find a syntax that works on both.