[wgsl] Rename smoothStep to smoothstep (#1800)

CHANGELOG.md

@@ -10,6 +10,7 @@
     - renames:
       - `findLsb` -> `firstTrailingBit`
       - `findMsb` -> `firstLeadingBit`
+      - `smoothStep` -> `smoothstep`
 
 ## v0.8 (2021-12-18)
   - development release for wgpu-0.12

src/back/wgsl/writer.rs

@@ -1517,7 +1517,7 @@ impl<W: Write> Writer<W> {
                     Mf::Fma => Function::Regular("fma"),
                     Mf::Mix => Function::Regular("mix"),
                     Mf::Step => Function::Regular("step"),
-                    Mf::SmoothStep => Function::Regular("smoothStep"),
+                    Mf::SmoothStep => Function::Regular("smoothstep"),
                     Mf::Sqrt => Function::Regular("sqrt"),
                     Mf::InverseSqrt => Function::Regular("inverseSqrt"),
                     Mf::Transpose => Function::Regular("transpose"),

src/front/wgsl/conv.rs

@@ -191,7 +191,7 @@ pub fn map_standard_fun(word: &str) -> Option<crate::MathFunction> {
         "fma" => Mf::Fma,
         "mix" => Mf::Mix,
         "step" => Mf::Step,
-        "smoothStep" => Mf::SmoothStep,
+        "smoothstep" => Mf::SmoothStep,
         "sqrt" => Mf::Sqrt,
         "inverseSqrt" => Mf::InverseSqrt,
         "transpose" => Mf::Transpose,