refactor: use 'some future' instead of 'next' major version

Co-authored-by: Luke Wagner <[email protected]>

Author: vados-cosmonic

design/mvp/WIT.md

@@ -1118,7 +1118,7 @@ interface calc {
 
 At this point, tooling consuming this WIT will be able to appropriately alert users to the now-deprecated `add-one` function.
 
-**Second: completely remove the deprecated item in the next SemVer-compliant major version**
+**Second: completely remove the deprecated item in some future SemVer-compliant major version**
 
 ```wit
 package examples:[email protected];