Short answer, yes.

how could it be included in a general syntax page?

I don't understand. But here's what i think: If we want to tell about commenting code, which is fine, it should tell

• how to write comments in that particular language (E.g. ' or Rem or // etc.)
• what to write and not to write
  • E.g. you don't write what the code does, i.e. explaining syntax, but rather semantic, concept etc. E.g. if x < 0 then x = 640 should be commented ' Wrap space-ship around the screen border and not something like ' set x to 640 if it is less then 0 as that is obvious to anyone who can read code.
• description of self commenting code
  • Self commenting code is mostly about correct use of indentation, spacing, both vertical and horizontal, naming conventions (e.g. Hungarian notation, though i am absolutely not a fan, just an example) and stuff like that. Basically how much you can inform the reader of what the code does without actually writing any comments. Self explaining code.