Bug 1863191 - Insert Menlo into the Japanese monospace font list on macOS, as fallback for Latin characters when Osaka-Mono is unavailable. r=layout-reviewers,emilio

Differential Revision: https://phabricator.services.mozilla.com/D192818

modules/libpref/init/all.js

@@ -2475,7 +2475,7 @@ pref("font.size.monospace.x-math", 13);
 
   pref("font.name-list.serif.ja", "Hiragino Mincho ProN, Hiragino Mincho Pro");
   pref("font.name-list.sans-serif.ja", "Hiragino Kaku Gothic ProN, Hiragino Kaku Gothic Pro, Hiragino Sans");
-  pref("font.name-list.monospace.ja", "Osaka-Mono, Hiragino Kaku Gothic ProN, Hiragino Sans");
+  pref("font.name-list.monospace.ja", "Osaka-Mono, Menlo, Hiragino Kaku Gothic ProN, Hiragino Sans");
 
   pref("font.name-list.serif.ko", "AppleMyungjo");
   pref("font.name-list.sans-serif.ko", "Apple SD Gothic Neo, AppleGothic");