upgrade docify to 0.2.5 (#2052)

Updates `docify` to 0.2.5, which fixes some indentation bugs and adds
the new `#[docify::export_content]` attribute which can be used like
regular `#[docify::export]` but will only export the _underlying
contents_ of the item it is attached to, if applicable (otherwise it
just behaves exactly like `#[docify::export]`).

Release notes here:
https://github.com/sam0x17/docify/releases/tag/v0.2.5

cc @kianenigma

substrate/frame/sudo/Cargo.toml

@@ -22,7 +22,7 @@ sp-io = { path = "../../primitives/io", default-features = false}
 sp-runtime = { path = "../../primitives/runtime", default-features = false}
 sp-std = { path = "../../primitives/std", default-features = false}
 
-docify = "0.2.4"
+docify = "0.2.5"
 
 [dev-dependencies]
 sp-core = { path = "../../primitives/core" }