Fix trailing whitespace

Author: freerich

frontend/asset_mapper.rst

@@ -200,8 +200,8 @@ this can be done by importing its full URL, like from a CDN:
 
     import { Alert } from 'https://cdn.jsdelivr.net/npm/bootstrap@5.3.0/+esm';
 
-But yikes! Needing to include that URL is a pain! Instead, we can add this package 
-to our "importmap" via the ``importmap:require`` command. This command can be used 
+But yikes! Needing to include that URL is a pain! Instead, we can add this package
+to our "importmap" via the ``importmap:require`` command. This command can be used
 to add any `npm package`_:
 
 .. code-block:: terminal
@@ -225,8 +225,8 @@ This adds the ``bootstrap`` package to your ``importmap.php`` file::
     such as ``@popperjs/core``. The ``importmap:require`` command will add both the
     main package *and* its dependencies.
 
-After adding/updating the package in your ``importmap.php`` file, all new packages 
-will be downloaded into an ``assets/vendor/`` directory. 
+After adding/updating the package in your ``importmap.php`` file, all new packages
+will be downloaded into an ``assets/vendor/`` directory.
 
 Now you can import the ``bootstrap`` package like usual:
 
@@ -235,8 +235,8 @@ Now you can import the ``bootstrap`` package like usual:
     import { Alert } from 'bootstrap';
     // ...
 
-It's recommended to ignore the ``assets/vendor/`` directory and not commit it to 
-your repository. Therefore, you'll need to run the ``php bin/console importmap:install`` 
+It's recommended to ignore the ``assets/vendor/`` directory and not commit it to
+your repository. Therefore, you'll need to run the ``php bin/console importmap:install``
 command to download the files on other computers if some files are missing:
 
 .. code-block:: terminal