Bump tui: 0.9 -> 0.12

[WizardOhio24]

Closes #205, Closes #285

Notable changes:

• Text -> Span
• Paragraph was changed such that '\n' no longer creates a new line, rather Spans (Vec<Span>) has to be used where each Spans would be a new line

(I've tried to fix all the paragraphs but if there is a paragraph which shows its elements horizontally rather than vertically, this PR is most likely the cause)

tui::widgets::Paragraph.title_style() is deprecated and command::CommandInfo.print() is no longer used, should these be fixed in this PR? (They're easy fixes)
Also, the test for line endings in DiffComponent was removed as it no longer applies.

[WizardOhio24]

There's now no more clippy warnings caused by upgrading tui to 0.11. The deprecations warnings have been fixed and command.print() has been removed.

[extrawurst]

@WizardOhio24 could you rebase, then nightly should work again

[WizardOhio24]

tui recently updated to 0.12 which allows Text to contain '\n' characters again. I can bump this to 0.12 but due to how tui 0.11 worked, all the Texts have been changed to Span/Spans. Although, the docs for tui do suggest using Span/Spans for multiple lines, https://docs.rs/tui/0.12.0/tui/text/index.html:

These types form a hierarchy: Spans is a collection of Span and each line of Text is a Spans.

[extrawurst]

@WizardOhio24 ok then lets stick to Span/Spans then. I guess that's the cleaner way to go. I did not check this PR yet, since I want to have the folder-folding stuff sorted before opening the next can :)

[extrawurst]

the line breaks in the commit details windows seem broken:

[extrawurst]

@WizardOhio24 thanks so much!