[eslint] fix linting error

Author: ljharb

src/components/DayPickerKeyboardShortcuts.jsx

@@ -102,6 +102,14 @@ class DayPickerKeyboardShortcuts extends React.PureComponent {
     this.handleFocus();
   }
 
+  handleFocus() {
+    if (this.hideKeyboardShortcutsButton) {
+      // automatically move focus into the dialog by moving
+      // to the only interactive element, the hide button
+      this.hideKeyboardShortcutsButton.focus();
+    }
+  }
+
   onKeyDown(e) {
     e.stopPropagation();
 
@@ -152,14 +160,6 @@ class DayPickerKeyboardShortcuts extends React.PureComponent {
     this.hideKeyboardShortcutsButton = ref;
   }
 
-  handleFocus() {
-    if (this.hideKeyboardShortcutsButton) {
-      // automatically move focus into the dialog by moving
-      // to the only interactive element, the hide button
-      this.hideKeyboardShortcutsButton.focus();
-    }
-  }
-
   render() {
     const {
       block,