Refactor interpolation modules and update CI workflow

Moved `Value` trait implementation for f32 and f64 to `value.rs` from `spline.rs`. Simplified the usage example in `linear.rs`. Updated CI workflow to use a dedicated action for installing 'nextest' and added a step for running documentation tests.

.github/workflows/ci.yaml

@@ -12,11 +12,9 @@ jobs:
       - uses: dtolnay/rust-toolchain@stable
         with:
           components: clippy, rustfmt
-      - name: Install nextest
-        shell: bash
-        run: |
-          curl -LsSf https://get.nexte.st/latest/linux | tar zxf - -C ${CARGO_HOME:-~/.cargo}/bin
+      - uses: taiki-e/install-action@nextest
       - run: cargo fmt --all --check
       - run: cargo check --workspace
       - run: cargo clippy --all-targets --all-features -- -D warnings
-      - run: cargo nextest run -E 'all() - package(calendar)'
+      - run: cargo nextest run -E 'all() - package(calendar)'
+      - run: cargo test --doc

crates/qlab-math/src/interpolation/linear.rs

@@ -15,11 +15,8 @@ use qlab_error::InterpolationError;
 /// use qlab_math::interpolation::linear::Linear;
 /// use qlab_math::interpolation::Interpolator;
 ///
-/// let mut linear: Linear<f32> = Linear::default();
-///
 /// let xs_and_ys: [(f32, f32); 2] = [(1.0_f32, 2.0_f32), (3.0_f32, 4.0_f32)];
-///
-/// linear.try_fit(&xs_and_ys).unwrap();
+/// let linear = Linear::default().try_fit(&xs_and_ys).unwrap();
 /// assert_eq!(linear.try_value(2.0).unwrap(), 3.0);
 ///
 /// ```

crates/qlab-math/src/interpolation/spline.rs

@@ -3,7 +3,3 @@ use crate::value::Value;
 pub mod catmull_rom;
 pub mod hermite;
 pub mod natural_cubic;
-
-impl Value for f32 {}
-
-impl Value for f64 {}

crates/qlab-math/src/value.rs

@@ -20,3 +20,7 @@ pub trait Value:
     + Default
 {
 }
+
+impl Value for f32 {}
+
+impl Value for f64 {}