add pre tags for html

src/render/formatted.zig

@@ -110,6 +110,7 @@ pub fn render(allocator: std.mem.Allocator, data: types.WeatherData, options: Re
     defer output.deinit();
 
     const w = &output.writer;
+    if (options.format == .html) try w.writeAll("<pre>");
     if (!options.no_caption)
         try w.print("Weather report: {s}\n\n", .{data.locationDisplayName()});
 
@@ -122,6 +123,7 @@ pub fn render(allocator: std.mem.Allocator, data: types.WeatherData, options: Re
             try renderForecastDay(w, day, options);
         }
     }
+    if (options.format == .html) try w.writeAll("</pre>");
 
     return output.toOwnedSlice();
 }