content [nfc]: Comment about not setting Heading weight relative to c…

…ontext

lib/widgets/content.dart

@@ -252,6 +252,11 @@ class Heading extends StatelessWidget {
           fontSize: kBaseFontSize * emHeight,
           height: 1.4,
         )
+          // Could set boldness relative to ambient text style, which itself
+          // might be bolder than normal (e.g. in spoiler headers).
+          // But this didn't seem like a clear improvement and would make inline
+          // **bold** spans less distinct; discussion:
+          //   https://github.com/zulip/zulip-flutter/pull/706#issuecomment-2141326257
           .merge(weightVariableTextStyle(context, wght: 600)),
         node: node));
   }