Let opt_interpolate return the plain string if path is None

Author: jannic

CHANGELOG-rust.md

@@ -5,6 +5,8 @@ This changelog tracks the Rust `svdtools` project. See
 
 ## [Unreleased]
 
+* If there is no path to interpolate, show unmodified `description`.
+
 ## [v0.3.13] 2024-03-29
 
 * Interpolate path and name in `description` and `derivedFrom`

src/patch/mod.rs

@@ -805,6 +805,7 @@ impl Spec for str {
 
 fn opt_interpolate<T: Interpolate>(path: &Option<&T>, s: Option<&str>) -> Option<String> {
     path.and_then(|path| path.interpolate_opt(s))
+        .or_else(|| s.map(ToString::to_string))
 }
 
 trait Interpolate {