fix condition mistake that doesn't actually affect anything

reader.js

@@ -18,7 +18,7 @@ browser.contextMenus.create({
 function might_have_japanese(text)
 {
     for(let char of text)
-        if(char && char.length > 0 && char.codePointAt(0) > 0x2E80)
+        if(char && char.length > 0 && char.codePointAt(0) >= 0x2E80)
             return true;
     return false;
 }