Various snippet improvements

[dltmtt]

Requirements

• Filling out the template is required. Any pull request that does not include enough information to be reviewed in a timely manner may be closed at the maintainers' discretion.
• All new code requires tests to ensure against regressions

Description of the Change

• Improved consistency in snippet names and in whitespace use
• Added a new snippet (fscanf)
• Improved snippet code readability and sorted them in a logical way
• Change scope of two snippets which where in the wrong section
• Improved quality of a few snippets

Alternate Designs

Other coding styleguides (such as brackets on their own line) where considered, but discarded for consistency with previous codebase

Benefits

• People who want to change the default snippets will have less trouble understanding them
• More consistency
• Snippets appear and work as expected

Possible Drawbacks

People used the the old names may be confused (even though they're basically the same).
I could revert that change if it's unwelcomed.

Applicable Issues

[dltmtt]

This is my first PR, I wasn't sure if I should have made multiple ones or not: the number of lines changed is not that big, but, while all relative to snippets, the changes include multiple areas (maybe a new snippet is welcomed but a code refactoring is not).
I tried to keep changes separated by commits, but please tell me if it's appropriate to create more PRs