doc: fix "maintaining dependencies" heading typos

Fix the obvious "IZA" typo. Also remove a period, since that seems to
match the rest of the doc folder.

PR-URL: #47082
Reviewed-By: Darshan Sen <raisinten@gmail.com>
Reviewed-By: Debadree Chatterjee <debadree333@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Danielle Adams <adamzdanielle@gmail.com>
Reviewed-By: Erick Wendel <erick.workspace@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>

doc/contributing/maintaining-dependencies.md

@@ -49,7 +49,7 @@ more of these reasons:
 3. They have a system wide configuration for the
    dependency that all applications should respect.
 
-## Supporting externalized dependencies with native code.
+## Supporting externalized dependencies with native code
 
 Support for externalized dependencies with native code for which a
 shared library is available can added by:
@@ -76,7 +76,7 @@ shared library is available can added by:
     }],
 ```
 
-## Supporting externalizable dependencies with JavaScript codeIZA
+## Supporting externalizable dependencies with JavaScript code
 
 Support for an externalizable dependency with JavaScript code
 can be added by: