feat: reset zoom to 1 with "r" shortcut

[g4rcez]

Description

Add shortcut R to reset zoom, by setting Z position to 1

[DanielGustavo]

Hi, I think it would be nice to add the new shortcut to the section "Default shortcuts" of the documentation:

Keystroke	Function
+/-	Zoom in/out (window must be focused)
r	Reset zoom (window must be focused)
/	Flip horizontal (window must be focused)
o	Toggle rounded camera (window must be focused)
Arrow Up / Down / Left / Right	Adjust video offset (window must be focused)
Ctrl+Shift+Alt+Up	Move camera to upper screen edge
Ctrl+Shift+Alt+Down	Move camera to lower screen edge
Ctrl+Shift+Alt+Right	Move camera to right screen edge
Ctrl+Shift+Alt+1	Set camera size to small
Ctrl+Shift+Alt+2	Set camera size to large
Ctrl+Shift+Alt+3	Toggle camera visibility

[g4rcez]

Done