Adds a keyboard shortcut (default Shift+M) that change the arc of fire at the selected turret.
Available options: full-range, 1/3 and 1/7.

Mod limitations

Only built turrets and their ghosts can be modified.

In Factorio 2.0, turrets collision box can be at an angle of 45°, which is why turrets larger than 2x2 have a different placing shape when oriented diagonally.
To position such turrets diagonally, take it in your hand, rotate 1 time and place it. Turret selection box should be at an angle of 45°. After limiting the arc of fire, you will be able to rotate the turret by 90°.

To safely remove the mod from your save, use /reset_turrets_turn_range command.