Improve filename consistency in the sources (#189)

* Improve source filename consistency

* Fix minor formatting

* Add release note

* code: apply pre-commit changes

* Update outputs using latest data from master

* Update release_notes.rst

* ruff fix

---------

Co-authored-by: Thomas Gilon <thomas.gilon@openenergytransition.org>
Co-authored-by: Fabrizio Finozzi <fabrizio.finozzi.business@gmail.com>
Co-authored-by: Lukas Trippe <lkstrp@pm.me>

Author: 4 people

docs/release_notes.rst

@@ -24,6 +24,8 @@ Upcoming Release
 
 * Align `snakemake` version and the related `mock_snakemake` to PyPSA-Eur (https://github.com/PyPSA/technology-data/pull/177)
 
+* Improve filename consistency in the sources (https://github.com/PyPSA/technology-data/pull/178)
+
 * Include further unit tests for compile_cost_assumptions_usa.py (https://github.com/PyPSA/technology-data/pull/182)
 
 * Updates the documentation with compile_cost_assumptions_usa.py (https://github.com/PyPSA/technology-data/pull/186)