MathAttach::primes: account for possible hash before base (#2363)

Fixes #2358.

crates/typst-syntax/src/ast.rs

@@ -863,7 +863,11 @@ impl<'a> MathAttach<'a> {
 
     /// Extract attached primes if present.
     pub fn primes(self) -> Option<MathPrimes<'a>> {
-        self.0.children().nth(1).and_then(|n| n.cast())
+        self.0
+            .children()
+            .skip_while(|node| node.cast::<Expr<'_>>().is_none())
+            .nth(1)
+            .and_then(|n| n.cast())
     }
 }
 

tests/typ/math/prime.typ

@@ -0,0 +1,9 @@
+// Test prime symbols after code mode.
+#let g = $f$
+#let gg = $f$
+
+$
+  #(g)' #g' #g ' \
+  #g''''''''''''''''' \
+  gg'
+$