fix: title underlines adjustements

Author: pcerqua-ipzs

docs/en/contribute.rst

@@ -15,7 +15,7 @@ Below are several methods available for contributing to this project:
 - **Developers Italia Slack channel**. Slack is a messaging application designed for businesses, connecting people to the information they need. *Developers Italia* is an open community based on contributions and participation from public administrations, developers, technicians, students, and citizens. *Developers Italia* has initiated a Slack channel that [everyone can join for free](https://slack.developers.italia.it/), where you can learn about all their activities and partake in discussions.
 
 Acknowledgements
-+++++++++++++++++++++++++++
+----------------
 
 We would like to thank the following individuals for their comments,
 concerns, ideas, contributions, some of which substantial, to this

docs/en/pseudonyms.inc

@@ -4,7 +4,7 @@
 
 
 Pseudonyms
-++++++++++
+==========
 
 
 What it is useful for