Register font by file path URL instead.

The documentation for `CTFontManagerRegisterGraphicsFont` at https://developer.apple.com/documentation/coretext/1499499-ctfontmanagerregistergraphicsfon hints that we should use `CTFontManagerRegisterFontsForURL` instead (since our fonts are backed by files in our bundle):

> Fonts that are backed by files should be registered using CTFontManagerRegisterFontsForURL(_:_:_:).

resources/src/appleMain/kotlin/dev/icerock/moko/resources/FontResource.kt

@@ -13,15 +13,22 @@ import kotlinx.cinterop.ptr
 import kotlinx.cinterop.value
 import platform.CoreFoundation.CFDataCreate
 import platform.CoreFoundation.CFErrorRefVar
+import platform.CoreFoundation.CFRelease
+import platform.CoreFoundation.CFStringRef
+import platform.CoreFoundation.CFURLCreateWithFileSystemPath
 import platform.CoreFoundation.kCFAllocatorDefault
+import platform.CoreFoundation.kCFURLPOSIXPathStyle
 import platform.CoreGraphics.CGDataProviderCreateWithCFData
 import platform.CoreGraphics.CGFontCreateWithDataProvider
 import platform.CoreGraphics.CGFontRef
-import platform.CoreText.CTFontManagerRegisterGraphicsFont
+import platform.CoreText.CTFontManagerRegisterFontsForURL
+import platform.CoreText.kCTFontManagerScopeProcess
 import platform.Foundation.CFBridgingRelease
+import platform.Foundation.CFBridgingRetain
 import platform.Foundation.NSBundle
 import platform.Foundation.NSData
 import platform.Foundation.NSError
+import platform.Foundation.NSString
 import platform.Foundation.create
 import platform.darwin.UInt8Var
 
@@ -59,14 +66,30 @@ actual class FontResource(
 
     @Throws(NSErrorException::class)
     @Suppress("unused")
-    fun registerFont() =
+    fun registerFont() {
+        // CAST_NEVER_SUCCEEDS - String is final and isn't castable, but on iOS it's
+        //  an NSString so `as NSString` is fine.
+        // UNCHECKED_CAST - NSString and CFStringRef are toll-free bridged
+        @Suppress("CAST_NEVER_SUCCEEDS", "UNCHECKED_CAST")
+        val cfStringFilePath = CFBridgingRetain(filePath as NSString) as CFStringRef
+        val cfFontUrlRef = CFURLCreateWithFileSystemPath(kCFAllocatorDefault, cfStringFilePath, kCFURLPOSIXPathStyle, false)
+
+        var nsError: NSError? = null
+
         memScoped {
             val error = alloc<CFErrorRefVar>()
-            if (!CTFontManagerRegisterGraphicsFont(fontRef, error.ptr)) {
+            if (!CTFontManagerRegisterFontsForURL(cfFontUrlRef, kCTFontManagerScopeProcess, error.ptr)) {
                 error.value?.let {
-                    val nsError = CFBridgingRelease(it) as NSError
-                    throw NSErrorException(nsError)
+                    nsError = CFBridgingRelease(it) as NSError
                 }
             }
         }
+
+        CFRelease(cfFontUrlRef)
+        CFRelease(cfStringFilePath)
+
+        nsError?.let {
+            throw NSErrorException(it)
+        }
+    }
 }