docs scrape examples

[Vrixyz]

docs.rs can link to examples which is helpful for understanding:

Part diff

index 5603c71..c90c83f 100644
--- a/crates/parry3d/Cargo.toml
+++ b/crates/parry3d/Cargo.toml
@@ -69,3 +81,13 @@ rstar = "0.12.0"
 oorandom = "11"
 ptree = "0.4.0"
 rand = { version = "0.8" }
+
+[[example]]
+name = "solid_ray_cast3d"
+path = "examples/solid_ray_cast3d.rs"
+doc-scrape-examples = true
+
+[package.metadata.docs.rs]
+rustdoc-args = ["-Zunstable-options", "--cfg", "docsrs"]
+all-features = true
+cargo-args = ["-Zunstable-options", "-Zrustdoc-scrape-examples"]