Update Migration.md

Co-authored-by: Addisu Z. Taddese <[email protected]>
Signed-off-by: Jose Luis Rivero <[email protected]>

Migration.md

@@ -9,8 +9,8 @@ release will remove the deprecated code.
 
 1. The minimum required cmake version is now 3.22.1.
 
-1. **Breaking**: C/C++ projects enable the visibility=hidden by default
-   gz-cmake4 changes the gz-cmake projects to use C/C++ visibility hidden
+1. **Breaking**: C/C++ projects enable the `visibility=hidden` compiler flag by default.
+   gz-cmake4 changes gz-cmake projects to use C/C++ visibility hidden
    by default. This is a potential breaking changed for projects using
    gz-cmake but the benefits in terms of creating portable code and
    time spend by the loader could be relevant.