Add parseYaml function for custom types

Author: RossComputerGuy

src/Yaml.zig

@@ -148,6 +148,10 @@ fn parseBoolean(self: Yaml, comptime T: type, value: Value) Error!T {
 fn parseUnion(self: Yaml, arena: Allocator, comptime T: type, value: Value) Error!T {
     const union_info = @typeInfo(T).@"union";
 
+    if (@hasDecl(T, "parseYaml")) {
+        return T.parseYaml(self, arena, value);
+    }
+
     if (union_info.tag_type) |_| {
         inline for (union_info.fields) |field| {
             if (self.parseValue(arena, field.type, value)) |u_value| {
@@ -174,6 +178,10 @@ fn parseStruct(self: Yaml, arena: Allocator, comptime T: type, map: Map) Error!T
     const struct_info = @typeInfo(T).@"struct";
     var parsed: T = undefined;
 
+    if (@hasDecl(T, "parseYaml")) {
+        return T.parseYaml(self, arena, .{ .map = map });
+    }
+
     inline for (struct_info.fields) |field| {
         var value: ?Value = map.get(field.name) orelse blk: {
             const field_name = try mem.replaceOwned(u8, arena, field.name, "_", "-");