Smart Eraser

📝 Description:
* This function will toggle between current tool and eraser tool, preserving a size of a brush so the eraser wouldn’t be too small or large;
💼 Photoshop analogue:
* Manually switching between tool and adjusting an eraser size manually;
👍 Usage:
* Best used when assigned to a hotkey (mine is E replacing the standard Eraser hotkey)