test(font): cover the Shx face variant in resolution test

`case_insensitive_ttf_resolution` matched `Face::resolve` against Ttf and
Lff only; the SHX shape-font variant added later left the match
non-exhaustive, which failed the whole lib-test build. Add the arm.

Co-Authored-By: Claude Fable 5 <[email protected]>

src/scene/text/font_face.rs

@@ -236,6 +236,10 @@ mod tests {
                     // they should resolve to Ttf. If they aren't installed, Lff fallback is accepted.
                     eprintln!("Font {} resolved to Lff (probably not installed)", test_name);
                 }
+                Face::Shx { .. } => {
+                    // A system TTF name never resolves to an SHX shape font.
+                    eprintln!("Font {} resolved to Shx (unexpected)", test_name);
+                }
             }
         }
     }