### 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
identifier = StringName();
	TkPos pos = { 0, 0 };
	Token tk = _get_token();
	if (tk.type == TK_IDENTIFIER) {
		identifier = tk.text;
		pos = _get_tkpos();
		tk = _get_token();
	}
	if (tk.type == TK_CURSOR) {
		completion_type = p_type;
		completion_line = tk_line;
		completion_block = p_block;
		pos = _get_tkpos();
		tk = _get_token();
		if (tk.type == TK_IDENTIFIER) {
			identifier = identifier.operator String() + tk.text.operator String();
		} else {
			_set_tkpos(pos);
		}
		return true;
	} else if (identifier != StringName()) {
		_set_tkpos(pos);
	}
	return false;
}
bool ShaderLanguage::_is_operator_assign(Operator p_op) const {