Fix save-and-reload-history command not found

[krapshsa]

The function save-and-reload-history is not exists.
Use _save-and-reload-history instead of save-and-reload-history.

Description

When I set BASH_IT_THEME='powerline',
it will show save-and-reload-history: command not found every time after starting a new command.
I found that other scripts use _save-and-reload-history instead of save-and-reload-history,
so I replace it with _save-and-reload-history.

Motivation and Context

It fixes "command not found."

How Has This Been Tested?

1. Set export BASH_IT_THEME='powerline in ~/.bashrc.
2. source ~/.bashrc
3. Press enter or some command.

Screenshots (if appropriate):

Types of changes

• 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)

Checklist:

• My code follows the code style of this project.
• If my change requires a change to the documentation, I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• If I have added a new file, I also added it to clean_files.txt and formatted it using lint_clean_files.sh.
• I have added tests to cover my changes, and all the new and existing tests pass.

[gaelicWizard]

Looks good to me 😃

[NoahGorny]

nice catch @krapshsa!
Thanks for the bugfix 😄