feat(rect): add Rect::positions iterator

[joshka]

Useful for performing some action on all the cells in a particular area. E.g.,

fn render(area: Rect, buf: &mut Buffer) {
   for position in area.positions() {
        buf.get_mut(position.x, position.y).set_symbol("x");
    }
}

[codecov]

Codecov Report

Attention: 3 lines in your changes are missing coverage. Please review.

Comparison is base (c3fb258) 92.0% compared to head (d0cab5a) 92.0%.

Files	Patch %	Lines
src/layout/rect.rs	0.0%	3 Missing ⚠️

Additional details and impacted files

@@          Coverage Diff          @@
##            main    #928   +/-   ##
=====================================
  Coverage   92.0%   92.0%           
=====================================
  Files         61      61           
  Lines      15521   15552   +31     
=====================================
+ Hits       14286   14315   +29     
- Misses      1235    1237    +2     

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[kdheepak]

Is there value in iterating vertically and horizontally? I'm not sure what to call it but the feature equivalent of positions_row_major() vs positions_column_major()?

[joshka]

Is there value in iterating vertically and horizontally? I'm not sure what to call it but the feature equivalent of positions_row_major() vs positions_column_major()?

Probably not, mainly because we're usually dealing with text, but area.columns().flat_map(Area::positions) gets you that in a one liner if needed.

[orhun]

LGTM