### Godot version

4.0.beta14

### System information

windows 10, gles 3, nvidia graphics

### Issue description

SCREEN_TEXTURE  was dropped in beta 14. The suggested replacement is to use ```uniform sampler2D SCREEN_TEXTURE : hint_screen_texture, filter_linear_mipmaps;```, but filter_linear_mipmaps is not recognized as a valid shader type hint and a shader using it fails to compile.

### Steps to reproduce

Create a canvas item shader and use the filter_linear_mipmaps type hint with a sampler2D uniform.

### Minimal reproduction project

N/A
if (p_node->type == Node::TYPE_OPERATOR) {
		OperatorNode *op = static_cast<OperatorNode *>(p_node);
		if (op->op == OP_INDEX) {
			return _validate_assign(op->arguments[0], p_function_info, r_message);
		} else if (_is_operator_assign(op->op)) {
			
			return _validate_assign(op->arguments[1], p_function_info, r_message);
		} else if (op->op == OP_CALL) {
			if (r_message) {
				*r_message = RTR("Assignment to function.");
			}
			return false;
		}
	} else if (p_node->type == Node::TYPE_MEMBER) {
		MemberNode *member = static_cast<MemberNode *>(p_node);
		if (member->has_swizzling_duplicates) {
			if (r_message) {
				*r_message = RTR("Swizzling assignment contains duplicates.");
			}
			return false;
		}
		return _validate_assign(member->owner, p_function_info, r_message);
	} else if (p_node->type == Node::TYPE_VARIABLE) {
		VariableNode *var = static_cast<VariableNode *>(p_node);
		if (shader->uniforms.has(var->name)) {