Change how we specify custom built-in names

src/builtin/flecs.core.zig

@@ -122,15 +122,14 @@ pub const Panic = struct {};
 
 // Query markers
 
+// zig fmt: off
 /// Query marker to express `$this` variable.
-pub const This = struct {};
+pub const This = struct { pub const name = "$"; };
-pub const _This_Name = "$";
 /// Query marker to express match all wildcard (`*` in query DSL).
-pub const Wildcard = struct {};
+pub const Wildcard = struct { pub const name = "*"; };
-pub const _Wildcard_Name = "*";
 /// Query marker to express match at least one wildcard (`_` in query DSL).
-pub const Any = struct {};
+pub const Any = struct { pub const name = "_"; };
-pub const _Any_Name = "_";
+// zig fmt: on
 
 /// Query marker to express `==` operator.
 pub const PredEq = struct {};

src/context.zig

@@ -150,8 +150,8 @@ pub fn Context(comptime ctx: anytype) type {
                 if (@TypeOf(ChildType) != type) continue;
 
                 comptime var child_name = decl.name;
-                if (@hasDecl(T, "_" ++ decl.name ++ "_Name"))
+                if (@hasDecl(ChildType, "name"))
-                    child_name = @field(T, "_" ++ decl.name ++ "_Name");
+                    child_name = @field(ChildType, "name");
 
                 const child = try lookupAndRegister(world, parent, child_name, ChildType, error_writer);
                 try lookupAndRegisterDeclarations(world, child, ChildType, error_writer);