editor: Represent scroll offset with more precision (#39367)

Closes #5355

Release Notes:

- Fixed rendering glitches with files with more than 16 million lines
(that occured due to floating number rounding errors).

---------

Co-authored-by: Smit Barmase <heysmitbarmase@gmail.com>

crates/text/src/selection.rs

@@ -5,8 +5,8 @@ use std::ops::Range;
 #[derive(Copy, Clone, Debug, PartialEq)]
 pub enum SelectionGoal {
     None,
-    HorizontalPosition(f32),
-    HorizontalRange { start: f32, end: f32 },
+    HorizontalPosition(f64),
+    HorizontalRange { start: f64, end: f64 },
     WrappedHorizontalPosition((u32, f32)),
 }