### 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_op) {
		case OP_ASSIGN:
		case OP_ASSIGN_ADD:
		case OP_ASSIGN_SUB:
		case OP_ASSIGN_MUL:
		case OP_ASSIGN_DIV:
		case OP_ASSIGN_MOD:
		case OP_ASSIGN_SHIFT_LEFT:
		case OP_ASSIGN_SHIFT_RIGHT:
		case OP_ASSIGN_BIT_AND:
		case OP_ASSIGN_BIT_OR:
		case OP_ASSIGN_BIT_XOR:
			return true;
		default:
			return false;
	}
}
bool ShaderLanguage::_validate_varying_assign(ShaderNode::Varying &p_varying, String *r_message) {
	if (current_function != "vertex" && current_function != "fragment") {
		*r_message = vformat(RTR("Varying may not be assigned in the '%s' function."), current_function);
		return false;
	}
	switch (p_varying.stage) {
		case ShaderNode::Varying::STAGE_UNKNOWN: