Preparing 5.5.0

[nunobrum]

This pull request updates PyLTSpice to version 5.5.0, introducing several codebase-wide improvements and some minor fixes. The most significant changes are the adoption of f-strings for string formatting throughout the code, dropping support for Python 3.9, and updating documentation and version numbers accordingly. Additionally, a minor code cleanup was performed in the examples.

General improvements and modernization:

• Replaced all string concatenations for simulation statistics output with f-strings across the codebase, including examples, documentation, and tests, for improved readability and consistency. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10]

• Updated documentation and changelog to announce version 5.5.0, note the drop of Python 3.9 support, and mention the adoption of f-strings and new union type hinting syntax. [1] [2]

• Updated the version number in pyproject.toml to 5.5.0.

Code cleanup and minor fixes:

• Cleaned up examples/raw_plotting.py by removing an unused import and improving parameter output formatting to align colons vertically using dynamic field width calculation. [1] [2]

• Fixed a typo in examples/sim_runner_asc_example.py ("simulatior" → "simulator").