add new multiple choice shortcuts

- added new multiple choice shortcuts for quickly selecting answers A-D. (#253)

README.md

@@ -51,6 +51,16 @@ Shortcuts that can only be used in exercises.
 | <kbd>CTRL</kbd>+<kbd>ALT</kbd>+<kbd>F</kbd> | Toggle Furigana on/off |
 | <kbd>CTRL</kbd>+<kbd>ALT</kbd>+<kbd>C</kbd> | Check answers (for written exercises) |
 
+##### Multiple Choice
+The following shortcuts can only be used in multiple choice exercises to quickly select an answer.
+
+| Shortcut | Description |
+| -------- | ----------- |
+| <kbd>ALT</kbd>+<kbd>A</kbd> | Selects option A |
+| <kbd>ALT</kbd>+<kbd>B</kbd> | Selects option B |
+| <kbd>ALT</kbd>+<kbd>C</kbd> | Selects option C |
+| <kbd>ALT</kbd>+<kbd>D</kbd> | Selects option D |
+
 
 ### Suggestions, Feedback, Bug Reports
 If you have any suggestions, feedback, questions, or bugs to report, feel free to [open a new discussion](https://github.com/SethClydesdale/genki-study-resources/discussions) in this repository. For alternative contact methods and detailed reporting information, please see the [report page](https://sethclydesdale.github.io/genki-study-resources/report/) for Genki Study Resources.

resources/javascript/all.js

@@ -195,5 +195,17 @@
         button.click();
       }
     }
+
+
+    // shortcuts for multi-choice options
+    // ALT + A/B/C/D
+    if (Genki.active.type == 'multi' && e.altKey && /a|b|c|d/i.test(e.key)) {
+      var opt = document.querySelector('#quiz-q' + Genki.stats.solved + ' div[data-option="' + e.key.toUpperCase() + '"]');
+
+      if (opt) {
+        opt.click();
+        e.preventDefault();
+      }
+    }
   });
 }(window, document));