Add missing doc comment

Summary:
It's self-explanatory what `style` is, but it's nice to note how
it's used because otherwise you have to dig around to find out.

Reviewed By: rchen152

Differential Revision: D82325998

fbshipit-source-id: fdc587a3628084efca612fc7d3511b703e475138

Author: stroxler

pyrefly/lib/binding/scope.rs

@@ -71,6 +71,7 @@ pub struct StaticInfo {
     pub annot: Option<Idx<KeyAnnotation>>,
     /// How many times this will be redefined
     pub count: usize,
+    /// How was this defined? Needed to determine the key for forward lookups.
     pub style: DefinitionStyle,
     /// Is this a mutable catpure of a definition in an outer scope (i.e. a global or a nonlocal)?
     pub is_mutable_capture: bool,