LibWeb/Layout: Add FIXMEs where we're using the wrong font

It's not clear how to address these right now, so add a FIXME to make
them easier to find and address later.

Libraries/LibWeb/Layout/BlockFormattingContext.cpp

@@ -1207,6 +1207,7 @@ void BlockFormattingContext::ensure_sizes_correct_for_left_offset_calculation(Li
     if (marker_text.is_empty()) {
         marker_state.set_content_width(image_width + default_marker_width);
     } else {
+        // FIXME: Use per-code-point fonts to measure text.
         auto text_width = marker.first_available_font().width(marker_text);
         marker_state.set_content_width(image_width + CSSPixels::nearest_value_for(text_width));
     }

Libraries/LibWeb/Layout/SVGFormattingContext.cpp

@@ -307,6 +307,7 @@ void SVGFormattingContext::layout_nested_viewport(Box const& viewport)
 Gfx::Path SVGFormattingContext::compute_path_for_text(SVGTextBox const& text_box)
 {
     auto& text_element = static_cast<SVG::SVGTextPositioningElement const&>(text_box.dom_node());
+    // FIXME: Use per-code-point fonts.
     auto& font = text_box.first_available_font();
     auto text_contents = text_element.text_contents();
     Utf8View text_utf8 { text_contents };
@@ -349,6 +350,7 @@ Gfx::Path SVGFormattingContext::compute_path_for_text_path(SVGTextPathBox const&
     if (!path_or_shape)
         return {};
 
+    // FIXME: Use per-code-point fonts.
     auto& font = text_path_box.first_available_font();
     auto text_contents = text_path_element.text_contents();
     Utf8View text_utf8 { text_contents };