minor #1537 [Doc] Fix a minor syntax issue in docs (javiereguiluz)

This PR was merged into the 2.x branch.

Discussion
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[Doc] Fix a minor syntax issue in docs

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| Issues        | -
| License       | MIT

Commits
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442e262 Update index.rst

Author: kbond

src/TwigComponent/doc/index.rst

@@ -306,7 +306,7 @@ want to render on the root element:
 
     <twig:Alert message="hello!" id="custom-alert-id" />
 
-To pass an array of attributes, use `{{...}}` spread operator syntax.
+To pass an array of attributes, use ``{{...}}`` spread operator syntax.
 This requires Twig 3.7.0 or higher:
 
 .. code-block:: html+twig