Documentation: wording change for 1,2,3,4

[Esshahn]

Documentation says

1: Paint with background color ($d021)
2: Paint with foreground color (Color RAM)
3: Paint with multicolor #1 color (if multicolor is enabled) ($d022)
4: Paint with multicolor #2 color (if multicolor is enabled) ($d023)

Pressing 1,2,3,4 doesn't actually change the color for painting, but tints the current cell (only).

Suggestion: Change "Paint" to "Fill selected cell"