provide node path on configuration

If you no provide node path in assetic configuration, UglifyCssFilter throw a  `RuntimeException: Path to node executable could not be resolved.`
Update uglifyjs.rst
Update uglifyjs.rst
update uglifyjs.rst
feature #4249 provide node path on configuration (desarrolla2)

This PR was merged into the 2.3 branch.

Discussion
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provide node path on configuration

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs? | No
| Applies to    | all
| Fixed tickets |

If you no provide node path in assetic configuration, UglifyCssFilter throw a  `RuntimeException: Path to node executable could not be resolved.`

Commits
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ab3dbef update uglifyjs.rst
1a5c0a6 Update uglifyjs.rst
1621071 Update uglifyjs.rst
2258ac9 provide node path on configuration