miniscript: Make operator""_mst consteval

src/script/miniscript.h

@@ -132,7 +132,7 @@ class Type {
 
 public:
     //! The only way to publicly construct a Type is using this literal operator.
-    friend constexpr Type operator""_mst(const char* c, size_t l);
+    friend consteval Type operator""_mst(const char* c, size_t l);
 
     //! Compute the type with the union of properties.
     constexpr Type operator|(Type x) const { return Type(m_flags | x.m_flags); }
@@ -154,7 +154,7 @@ public:
 };
 
 //! Literal operator to construct Type objects.
-inline constexpr Type operator""_mst(const char* c, size_t l)
+inline consteval Type operator""_mst(const char* c, size_t l)
 {
     Type typ{0};