Convert unnecessary class funcs to static

Author: STREGA

Sources/GateEngine/Resources/Importers/ApplePlatformImageImporter.swift

@@ -29,7 +29,7 @@ public final class ApplePlatformImageImporter: TextureImporter {
         return (data, size)
     }
 
-    public class func canProcessFile(_ file: URL) -> Bool {
+    public static func canProcessFile(_ file: URL) -> Bool {
         guard let identifiers = (CGImageSourceCopyTypeIdentifiers() as? [CFString]) else {
             return false
         }

Sources/GateEngine/Resources/Importers/PNGImporter.swift

@@ -14,7 +14,7 @@ public final class PNGImporter: TextureImporter {
         return try decode(data: data, size: size, options: options)
     }
 
-    public class func canProcessFile(_ file: URL) -> Bool {
+    public static func canProcessFile(_ file: URL) -> Bool {
         return file.pathExtension.caseInsensitiveCompare("png") == .orderedSame
     }
 }

Sources/GateEngine/Resources/Skinning/Skeleton.swift

@@ -375,7 +375,7 @@ extension Skeleton.Joint {
 }
 
 extension Skeleton.Joint: Hashable {
-    final public class func == (lhs: Skeleton.Joint, rhs: Skeleton.Joint) -> Bool {
+    public static func == (lhs: Skeleton.Joint, rhs: Skeleton.Joint) -> Bool {
         return lhs.id == rhs.id
     }
 

Sources/GateEngine/System/Platforms/Win32/Win32/Win32Window.swift

@@ -156,7 +156,7 @@ final class Win32Window: WindowBacking {
 }
 
 extension Win32Window {
-    fileprivate class func makeHWND(withSize size: Size2, style: Win32WindowStyle) -> HWND {
+    fileprivate static func makeHWND(withSize size: Size2, style: Win32WindowStyle) -> HWND {
         let dwExStyle: DWORD = 0
         let lpClassName: [WCHAR] = "\(type(of: Win32Window.self))".windowsUTF16
         let lpWindowName: [WCHAR] = ProcessInfo.processInfo.processName.windowsUTF16