re_format: add general format_int function (#5754)

### What
Mostly as an experiment to see if this makes sense as a `trait` for
`num-traits` (see rust-num/num-traits#315)

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- [PR Build Summary](https://build.rerun.io/pr/5754)
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crates/re_format/src/lib.rs

@@ -7,6 +7,8 @@ pub mod arrow;
 
 mod time;
 
+use std::{cmp::PartialOrd, fmt::Display};
+
 pub use time::next_grid_tick_magnitude_ns;
 
 // --- Numbers ---
@@ -16,30 +18,97 @@ pub use time::next_grid_tick_magnitude_ns;
 /// Looks slightly different from the normal hyphen `-`.
 const MINUS: char = '−';
 
-/// Pretty format an unsigned integer by using thousands separators for readability.
-///
-/// The returned value is for human eyes only, and can not be parsed
-/// by the normal `usize::from_str` function.
-pub fn format_uint<Uint>(number: Uint) -> String
-where
-    Uint: Copy + num_traits::Unsigned + std::fmt::Display,
-{
-    add_thousands_separators(&number.to_string())
+// TODO(rust-num/num-traits#315): waiting for https://github.com/rust-num/num-traits/issues/315 to land
+pub trait UnsignedAbs {
+    /// An unsigned type which is large enough to hold the absolute value of `Self`.
+    type Unsigned;
+
+    /// Computes the absolute value of `self` without any wrapping or panicking.
+    fn unsigned_abs(self) -> Self::Unsigned;
+}
+
+impl UnsignedAbs for i8 {
+    type Unsigned = u8;
+
+    #[inline]
+    fn unsigned_abs(self) -> Self::Unsigned {
+        self.unsigned_abs()
+    }
+}
+
+impl UnsignedAbs for i16 {
+    type Unsigned = u16;
+
+    #[inline]
+    fn unsigned_abs(self) -> Self::Unsigned {
+        self.unsigned_abs()
+    }
+}
+
+impl UnsignedAbs for i32 {
+    type Unsigned = u32;
+
+    #[inline]
+    fn unsigned_abs(self) -> Self::Unsigned {
+        self.unsigned_abs()
+    }
+}
+
+impl UnsignedAbs for i64 {
+    type Unsigned = u64;
+
+    #[inline]
+    fn unsigned_abs(self) -> Self::Unsigned {
+        self.unsigned_abs()
+    }
+}
+
+impl UnsignedAbs for i128 {
+    type Unsigned = u128;
+
+    #[inline]
+    fn unsigned_abs(self) -> Self::Unsigned {
+        self.unsigned_abs()
+    }
+}
+
+impl UnsignedAbs for isize {
+    type Unsigned = usize;
+
+    #[inline]
+    fn unsigned_abs(self) -> Self::Unsigned {
+        self.unsigned_abs()
+    }
 }
 
 /// Pretty format a signed number by using thousands separators for readability.
 ///
 /// The returned value is for human eyes only, and can not be parsed
 /// by the normal `usize::from_str` function.
-pub fn format_i64(number: i64) -> String {
-    if number < 0 {
-        // TODO(rust-num/num-traits#315): generalize this to all signed integers once https://github.com/rust-num/num-traits/issues/315 lands
+pub fn format_int<Int>(number: Int) -> String
+where
+    Int: Display + PartialOrd + num_traits::Zero + UnsignedAbs,
+    Int::Unsigned: Display + num_traits::Unsigned,
+{
+    if number < Int::zero() {
         format!("{MINUS}{}", format_uint(number.unsigned_abs()))
     } else {
         add_thousands_separators(&number.to_string())
     }
 }
 
+/// Pretty format an unsigned integer by using thousands separators for readability.
+///
+/// The returned value is for human eyes only, and can not be parsed
+/// by the normal `usize::from_str` function.
+#[allow(clippy::needless_pass_by_value)]
+pub fn format_uint<Uint>(number: Uint) -> String
+where
+    Uint: Display + num_traits::Unsigned,
+{
+    add_thousands_separators(&number.to_string())
+}
+
 /// Add thousands separators to a number, every three steps,
 /// counting from the last character.
 fn add_thousands_separators(number: &str) -> String {

crates/re_log_types/src/time_point/mod.rs

@@ -139,7 +139,7 @@ impl TimeType {
         } else {
             match self {
                 Self::Time => Time::from(time_int).format(time_zone_for_timestamps),
-                Self::Sequence => format!("#{}", re_format::format_i64(time_int.0)),
+                Self::Sequence => format!("#{}", re_format::format_int(time_int.0)),
             }
         }
     }

crates/re_time_panel/src/paint_ticks.rs

@@ -92,7 +92,7 @@ fn paint_time_range_ticks(
                 &ui.clip_rect(),
                 time_range,
                 next_power_of_10,
-                |seq| format!("#{}", re_format::format_i64(seq)),
+                |seq| format!("#{}", re_format::format_int(seq)),
             )
         }
     }