Add documentation for SymbolScaleBehavior (#10865)

Adds documentation for SymbolScaleBehavior introduced
[here](mapbox/mapbox-sdk#9946).

<img width="676" height="550" alt="Screenshot 2026-03-09 at 9 42 55 AM"
src="https://github.com/user-attachments/assets/da2d4353-3868-4660-bd54-b57883cceec5"
/>

cc @mapbox/maps-ios

GitOrigin-RevId: dc5d4613c595c9dd5788d168d4b9df2e9c317c05

Author: pjleonard37

Sources/MapboxMaps/Documentation.docc/API Catalogs/MapboxMap APIs.md

@@ -20,6 +20,7 @@
 - ``MapCenterAltitudeMode``
 - ``RenderedQueryGeometry``
 - ``RenderedQueryGeometryConvertible``
+- ``SymbolScaleBehavior``
 
 ### Camera
 - ``FreeCameraOptions``

Sources/MapboxMaps/Foundation/MapboxMap.swift

@@ -1120,6 +1120,7 @@ public final class MapboxMap: StyleManager {
     /// symbolScaleBehavior = .system  // Auto-scale
     /// symbolScaleBehavior = .system { min($0 * 1.2, 1.5) }  // Custom
     /// ```
+    @_documentation(visibility: public)
     @_spi(Experimental)
     public var symbolScaleBehavior: SymbolScaleBehavior = .fixed(scaleFactor: 1.0) {
         didSet {

Sources/MapboxMaps/Foundation/SymbolScaleBehavior.swift

@@ -6,6 +6,7 @@ import UIKit
 /// Use factory methods to create instances:
 /// - `.system` - Automatic scaling with default or custom mapping
 /// - `.fixed(scaleFactor:)` - Fixed scale factor, no dynamic updates
+@_documentation(visibility: public)
 @_spi(Experimental)
 public struct SymbolScaleBehavior: Equatable {
     internal enum Mode {

scripts/api-compatibility-check/breakage_allowlist.txt

@@ -2254,3 +2254,6 @@ Extension String has removed conformance to RegexComponent
 Constructor Model.init(id:uri:position:orientation:) has been removed
 // Update experimental Marker interaction APIs
 Func Marker.onTapGesture(perform:) has been removed
+
+Struct SymbolScaleBehavior is now with @_documentation
+Var MapboxMap.symbolScaleBehavior is now with @_documentation