docs(ramp): backtick the [0,1] interval so rustdoc stops reading it as a link

`cargo doc` warned "unresolved link to `0,1`" on progress(): rustdoc treats
bracketed prose as an intra-doc link, and the clamp interval looked like an
item path. Backticks say what it is — a range, not a reference — and fix the
warning as a side effect; `\[0,1\]` would silence it without that.

The crate's rustdoc is clean again, which is the point: one standing warning
is how the next real broken link goes unnoticed.

Co-Authored-By: Claude Opus 5 <[email protected]>

 src/ramp.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/ramp.rs b/src/ramp.rs
index 70b2dd9..6a0ae25 100644
--- a/src/ramp.rs
+++ b/src/ramp.rs
@@ -131,7 +131,7 @@ impl SpeedRamp {
     }
 
     /// Progress through the transition at normalized time `t` (clamped to
-    /// [0,1]): 0 at start, exactly 1 at the end, monotonic.
+    /// `[0,1]`): 0 at start, exactly 1 at the end, monotonic.
     pub fn progress(&self, t: f64) -> f64 {
         if t <= 0.0 {
             return 0.0;