src/vs/workbench/contrib/terminal/browser/terminalInstance.ts/TerminalInstance/setFixedDimensions
class TerminalInstance:	async setFixedDimensions(): Promise<void> {
		const cols = await this._quickInputService.input({
			title: nls.localize('setTerminalDimensionsColumn', "Set Fixed Dimensions: Column"),
			placeHolder: 'Enter a number of columns or leave empty for automatic width',
			validateInput: async (text) => text.length > 0 && !text.match(/^\d+$/) ? { content: 'Enter a number or leave empty size automatically', severity: Severity.Error } : undefined
		});
		if (cols === undefined) {
			return;
		}
		this._fixedCols = this._parseFixedDimension(cols);
		this._labelComputer?.refreshLabel();
		this._terminalHasFixedWidth.set(!!this._fixedCols);
		const rows = await this._quickInputService.input({
			title: nls.localize('setTerminalDimensionsRow', "Set Fixed Dimensions: Row"),
			placeHolder: 'Enter a number of rows or leave empty for automatic height',
			validateInput: async (text) => text.length > 0 && !text.match(/^\d+$/) ? { content: 'Enter a number or leave empty size automatically', severity: Severity.Error } : undefined
		});
		if (rows === undefined) {
			return;
		}
		this._fixedRows = this._parseFixedDimension(rows);
		this._labelComputer?.refreshLabel();
		await this._refreshScrollbar();
		this._resize();
		this.focus();
	}