### 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
switch (p_node->type) {
		case Node::TYPE_OPERATOR: {
			const OperatorNode *op_node = static_cast<const OperatorNode *>(p_node);
			for (int i = int(op_node->op == OP_CALL); i < op_node->arguments.size(); i++) {
				if (!_check_node_constness(op_node->arguments[i])) {
					return false;
				}
			}
		} break;
		case Node::TYPE_CONSTANT:
			break;
		case Node::TYPE_VARIABLE: {
			const VariableNode *varn = static_cast<const VariableNode *>(p_node);
			if (!varn->is_const) {
				return false;
			}
		} break;
		case Node::TYPE_ARRAY: {
			const ArrayNode *arrn = static_cast<const ArrayNode *>(p_node);
			if (!arrn->is_const) {
				return false;
			}
		} break;
		default:
			return false;
	}
	return true;
}
bool ShaderLanguage::_validate_assign(Node *p_node, const FunctionInfo &p_function_info, String *r_message) {