Spreadsheet: Add Range(s).toArray()

Author: https://github.com/u9g
Commit: 93115ee044
Pull-request: https://github.com/SerenityOS/serenity/pull/12853
Reviewed-by: https://github.com/alimpfard

Userland/Applications/Spreadsheet/Tests/mock.test-common.js

@@ -136,7 +136,7 @@ class Sheet {
             if (column !== name) continue;
             bound = Math.max(bound, row);
         }
-        return row;
+        return bound;
     }
 
     evaluate(currentColumn, currentRow, expression) {