Fix typos in the src/ subdirectory

[luzpaz]

Description

Fixes all comment or documentation typos in the src/ subdir
Found via codespell -q 3 -S *.po,*.pot,*.utf8,ChangeLog,./src/external,./plugins/RemoteControl/webroot/js -L anonymus,dout,inout,lod,ned,ser,te,tht,ue

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• This change requires a documentation update
• Housecleaning

How Has This Been Tested?

n/a

Checklist:

• My code follows the code style of this project.
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation (header file)
• I have updated the respective chapter in the Stellarium User Guide
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[github-actions]

Great PR! Please pay attention to the following items before merging:

Files matching src/**/*.cpp:

• Are possibly unused includes removed?

This is an automatically generated QA checklist based on modified files

[github-actions]

Thanks for adding your first pull request to Stellarium. If you have questions, please do not hesitate to contact us.

[gzotti]

Well done!

[github-actions]

Hello @luzpaz!

Please check the fresh version (development snapshot) of Stellarium:
https://github.com/Stellarium/stellarium-data/releases/tag/weekly-snapshot

[github-actions]

Hello @luzpaz!

Please check the latest stable version of Stellarium:
https://github.com/Stellarium/stellarium/releases/latest

[luzpaz]

MY machine crashed after a manjaro update. I can't check ATM.