Add standard text find and replace

[guanglinn]

This PR makes Markor support the standard text find/search and replace adopted by many other popular text editors.

#2164 #2341

Supported features are as follows:

1. Standard UI for text find & replace

2. Highlight all occurrences/matches

3. Highlight current match

4. Move to previous/next match

5. Match case

6. Match whole word

7. Use regular expression

8. Find in selection

9. Replace once

10. Replace all

11. Preserve case when replacing

[guanglinn]

Screenshot ↓

[gsantner]

Thanks for working on this and the screenshot! To me at least it looks quite complicated at first, user will next ask where can I replace only this highlighted one? Where can I replace all? Thats the two most important buttons to be easy recognizable

[guanglinn]

User will next ask where can I replace only this highlighted one?
Where can I replace all?

These two features have already been implemented in this PR, and these two buttons can popup tool tips, users can easily recognize it.

[guanglinn]

Does this get rid of the existing search dialog for todo? Because that had multi-selection and inline search - making it easy to read through and filter todos

This feature didn't get rid of the existing search dialog for todo, it didn't affect todo.

[gsantner]

Thanks both! Also for the review harshad, seems like it's not good enough yet to unleash on users, right?

[guanglinn]

Right. It works now too, but it's not as perfect in occurrence highlighting. I will take the time to improve it, probably in many days.

[gsantner]

@guanglinn
Thank you, sure feel free to take the time when it fits

[guanglinn]

Sorry, this PR has been put on hold for a long time. I will continue to improve it in these days.

[guanglinn]

Icons are from microsoft/vscode-icons: Icons for Visual Studio Code

[gsantner]

Hello guanglinn, what did you mean with visual studio code icons?

If a option viable, at Markor normal Android icon set is used

[guanglinn]

I mean, the icons used for this new find & replace are from vscode-icons, this is a open source icon set, and it's nice, so I just made a declaration here to indicate that we used it.