chore: try to comply to C++20

[realstealthninja]

Description of Change

Added more include statements
fixed a compilation error when an explicit function had template brackets in its definition.
linted all files that were modified.

Checklist

• Added description of change
• Added file name matches File name guidelines
• [ ] Added tests and example, test must pass
• Added documentation so that the program is self-explanatory and educational - Doxygen guidelines
• Relevant documentation/comments is changed or added
• PR title follows semantic commit guidelines
• Search previous suggestions before making a new one, as yours may be a duplicate.
• I acknowledge that all my contributions will be made under the project's license.

Notes: