doc: fix quoting on Constructible and manually update nightly compiler

Looks like the "update nightly rustc" cronjob is working #303 but
the latest nightly isn't working because our docs have a broken
link.

Author: apoelstra

nightly-version

@@ -1 +1 @@
-nightly-2025-04-11
+nightly-2025-08-29

src/node/mod.rs

@@ -616,7 +616,7 @@ impl<N: Marker> Node<N> {
     /// automatically based on the value of `inner` but requires that `cached_data`
     /// be provided.
     ///
-    /// If available, [`Constructible'] and its dependent traits will be easier to
+    /// If available, [`Constructible`] and its dependent traits will be easier to
     /// use.
     pub fn from_parts(
         inner: Inner<Arc<Self>, N::Jet, N::Disconnect, N::Witness>,