Add ruler to histogram output

[DimitrisVita]

Your checklist for this pull request

• I've read the guidelines for contributing to this repository
• I made sure to follow the project's coding style
• I've documented or updated the documentation of every function and struct this PR changes. If not so I've explained why.
• I've added tests that prove my fix is effective or that my feature works (if possible)
• I've updated the rizin book with the relevant information (if needed)

Detailed description

This pull request adds a vertical ruler to the horizontal histogram output in librz/cons/histogram.c. The ruler includes value ranges and uses a vertical Unicode line character if scr.utf8=true.

I've added y-axis numbering, which is computed as 255 - threshold, where the threshold is calculated for each row. Please let me know if this approach is acceptable or if any adjustments are needed. Should it be added to the interactive histogram too?

Here are two images showing the expected output:

• Image 1: p== 50 with scr.utf8=true

• Image 2: p== 50 with scr.utf8=false

Test plan

1. Enable scr.utf8=true in the configuration.
2. Generate a horizontal histogram using the p== command.
3. Verify that the vertical ruler is displayed correctly with value ranges.
4. Disable scr.utf8=true and repeat the test to ensure the ruler is displayed correctly without Unicode characters.

Closing issues

Addresses #129 but might need improvement

[XVilka]

In such PRs (related to UI) please attach screenshots.

[XVilka]

@DimitrisVita I think such ruler should be moved to the left, not the right. Or this can be one more histogram option

[XVilka]

I also think, that while vertical ruler should be added to horizontal histogram, horitzontal ruler should be added to vertical histogram.

[XVilka]

@DimitrisVita hi, have you had some time to continue working on this?

[notxvilka]

@DimitrisVita if you have any questions, don't hesitate to ask them on the Rizin Dev channel on our Mattermost.