src/vs/workbench/contrib/terminal/browser/terminalConfigHelper.ts/TerminalConfigHelper/configFontIsMonospace
class TerminalConfigHelper:	configFontIsMonospace(): boolean {
		const fontSize = 15;
		const fontFamily = this.config.fontFamily || this._configurationService.getValue<IEditorOptions>('editor').fontFamily || EDITOR_FONT_DEFAULTS.fontFamily;
		const iRect = this._getBoundingRectFor('i', fontFamily, fontSize);
		const wRect = this._getBoundingRectFor('w', fontFamily, fontSize);

		// Check for invalid bounds, there is no reason to believe the font is not monospace
		if (!iRect || !wRect || !iRect.width || !wRect.width) {
			return true;
		}

		return iRect.width === wRect.width;
	}