fix(docs): readInlineData function (#4451)

Summary:
> * pass a reference to an `inline` fragment, which can then be accessed (outside of the render phase) using the `readInlineData` function.

`readInlineData` is a function, not a directive.

Pull Request resolved: #4451

Reviewed By: captbaritone

Differential Revision: D50011992

Pulled By: alunyov

fbshipit-source-id: 56401b32f1eb771cf2f53f2799f6aee6941e8d50

website/docs/glossary/glossary.md

@@ -393,7 +393,7 @@ A directive that applies to fragments which enables developers to pass masked da
 Normally, data is read out using `useFragment`. However, this function can only be called during the render phase. If store data is needed in a outside of the render phase, a developer has several options:
 
 * read that data during the render phase, and pass it to the function/have the function close over that data. (See also [#relay])
-* pass a reference to an `@inline` fragment, which can then be accessed (outside of the render phase) using the `readInlineData` directive.
+* pass a reference to an `@inline` fragment, which can then be accessed (outside of the render phase) using the `readInlineData` function.
 
 This directive causes them to be read out when the parent fragment is read out, and unmasked by the call to `readInlineData`.