Don't change overview ruler position based on decorations
Don't change overview ruler position based on decorations

The original fix for #3705 ended up revealing this other bug; the canvas
shouldn't be set based on the anchor of its decorations.

Fixes #3705

xtermjs/xterm.js,xtermjs/xterm.js,Tyriar/xterm.js,xtermjs/xterm.js,xtermjs/xterm.js,Tyriar/xterm.js,Tyriar/xterm.js,xtermjs/xterm.js,Tyriar/xterm.js,Tyriar/xterm.js