src/vs/workbench/contrib/terminal/browser/terminalGroup.ts/TerminalGroup/resizePane
class TerminalGroup:	resizePane(direction: Direction): void {
		if (!this._splitPaneContainer) {
			return;
		}

		const isHorizontal = (direction === Direction.Left || direction === Direction.Right);
		const font = this._terminalService.configHelper.getFont();
		// TODO: Support letter spacing and line height
		const amount = isHorizontal ? font.charWidth : font.charHeight;
		if (amount) {
			this._splitPaneContainer.resizePane(this._activeInstanceIndex, direction, amount);
		}
	}