Sema: add error for non-comptime param in comptime func

Adds error for taking a non comptime parameter in a function returning a
comptime-only type but not when that type is dependent on a parameter.

Co-authored-by: Veikka Tuominen <git@vexu.eu>

lib/std/multi_array_list.zig

@@ -459,7 +459,7 @@ pub fn MultiArrayList(comptime S: type) type {
             return self.bytes[0..capacityInBytes(self.capacity)];
         }
 
-        fn FieldType(field: Field) type {
+        fn FieldType(comptime field: Field) type {
             return meta.fieldInfo(S, field).field_type;
         }