Rollup merge of rust-lang#146299 - smirzaei:doc/improve-path-canonicalize-docs, r=jhpratt

docs(std): add error docs for path canonicalize

This PR adds the missing error documentation for both [Path.canonicalize](https://doc.rust-lang.org/std/path/struct.Path.html#method.canonicalize) and [PathBuf.canonicalize](https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.canonicalize) methods. Since both methods are wappers around [fs::canonicalize](https://doc.rust-lang.org/std/fs/fn.canonicalize.html), the error doc is copied directly from that function.

This makes it faster to find what errors might arise when calling `path.canonicalize` or `path_buf.canonicalize` in the editor itself without needing to drill down to the  `fs::canonicalzie` docs.

Author: matthiaskrgr

library/std/src/path.rs

@@ -3037,6 +3037,14 @@ impl Path {
     ///
     /// This is an alias to [`fs::canonicalize`].
     ///
+    /// # Errors
+    ///
+    /// This method will return an error in the following situations, but is not
+    /// limited to just these cases:
+    ///
+    /// * `path` does not exist.
+    /// * A non-final component in path is not a directory.
+    ///
     /// # Examples
     ///
     /// ```no_run