Perhaps worth measuring initial indent for variable-width fonts?

[joliss]

I wonder if it's worth measuring the pixel-width of the initial indent using view.coordsAtPos, rather than using ${numColumns}ch, in order to accommodate variable-width fonts.

Here's a screenshot of my CodeMirror instance for editing Markdown, which uses syntax highlighting with both monospaced and variable-width fonts. The monospaced indent works fine, but with variable-width, we indent too much, because 1ch is wider than a sans-serif blank space.