Spell 'includes' correctly

Author: hsutter

include/cpp2util.h

@@ -1755,7 +1755,7 @@ using cpp2::cpp2_new;
 // See commit 5a0d77f8e297902c0b9712c5aafb6208cfa4c139.
 #if !defined(__clang__) && defined(__GNUC__) && __GNUC__ == 10
     #define CPP2_REQUIRES(...) /* empty */
-    #define CPP2_REQUIRES_MEMFN(...) static_assert(false, "GCC 11 or higher is required to support type-scope functions that have a 'requires' clause. This includs a 'forward' parameter of non-wildcard type, such as 'func: (this, forward s: std::string)', which relies on being able to add a 'requires' clause - in that case, use 'forward s: _' instead if you need the result to compile with GCC 10.")
+    #define CPP2_REQUIRES_MEMFN(...) static_assert(false, "GCC 11 or higher is required to support type-scope functions that have a 'requires' clause. This includes a 'forward' parameter of non-wildcard type, such as 'func: (this, forward s: std::string)', which relies on being able to add a 'requires' clause - in that case, use 'forward s: _' instead if you need the result to compile with GCC 10.")
 #else
     #define CPP2_REQUIRES(...) requires (__VA_ARGS__)
     #define CPP2_REQUIRES_MEMFN(...) requires (__VA_ARGS__)