[rs] Add include_wgsl!() macro (#922)

* Add include_wgsl macro

* Add include_wgsl macro

* Change ShaderFlags to all

wgpu/src/macros.rs

@@ -57,3 +57,18 @@ macro_rules! include_spirv {
         }
     };
 }
+
+/// Macro to load a WGSL module statically.
+#[macro_export]
+macro_rules! include_wgsl {
+    ($($token:tt)*) => {
+        {
+            //log::info!("including '{}'", $($token)*);
+            $crate::ShaderModuleDescriptor {
+                label: Some($($token)*),
+                source: $crate::ShaderSource::Wgsl(include_str!($($token)*).into()),
+                flags: $crate::ShaderFlags::all(),
+            }
+        }
+    };
+}