Added visibility' grammar
# Visibility and Privacy
+> **<sup>Syntax<sup>**
+> _Visibility_ :
+> &nbsp;&nbsp; &nbsp;&nbsp; EMPTY
+> &nbsp;&nbsp; | `pub`
+> &nbsp;&nbsp; | `pub` `(` `crate` `)`
+> &nbsp;&nbsp; | `pub` `(` `in` _ModulePath_ `)`
+> &nbsp;&nbsp; | `pub` `(` `in`<sup>?</sup> `self` `)`
+> &nbsp;&nbsp; | `pub` `(` `in`<sup>?</sup> `super` `)`
+
These two terms are often used interchangeably, and what they are attempting to
convey is the answer to the question "Can this item be used at this location?"
