Removing the mention of using discard for block comments

[elliotwaite]

The removed line mentions that the comments section describes how to use the discard statement to create block comments. However, the comments section does not mention using a discard statement. It instead only mentions using the #[ and ]# syntax. If that is the new preferred method of creating block comments, perhaps this line should be removed, which is what this change does.

Alternatively, if the documentation wants to present both solutions, I could instead update this change to replace the link to the comments section with an inline explanation of how you can also use the discard statement with long string literals to create block comments. If this would be preferred, let me know and I can update this pull request.

[Araq]

It was decided back then not to mention the usage of discard for comments in the tutorials.