Fix typo in footnote reference

Author: felicitymay

docs/codeql/support/reusables/versions-compilers.rst

@@ -21,7 +21,7 @@
 
    Eclipse compiler for Java (ECJ) [5]_",``.java``
    JavaScript,ECMAScript 2022 or lower,Not applicable,"``.js``, ``.jsx``, ``.mjs``, ``.es``, ``.es6``, ``.htm``, ``.html``, ``.xhtm``, ``.xhtml``, ``.vue``, ``.hbs``, ``.ejs``, ``.njk``, ``.json``, ``.yaml``, ``.yml``, ``.raml``, ``.xml`` [6]_"
-   Python [7],"2.7, 3.5, 3.6, 3.7, 3.8, 3.9, 3.10",Not applicable,``.py``
+   Python [7]_,"2.7, 3.5, 3.6, 3.7, 3.8, 3.9, 3.10",Not applicable,``.py``
    Ruby [8]_,"up to 3.0.2",Not applicable,"``.rb``, ``.erb``, ``.gemspec``, ``Gemfile``"
    TypeScript [9]_,"2.6-4.8",Standard TypeScript compiler,"``.ts``, ``.tsx``, ``.mts``, ``.cts``"