Update posts/specfile-advanced/index.md

Co-authored-by: Laura Barcziová <[email protected]>

posts/specfile-advanced/index.md

@@ -54,7 +54,7 @@ It is also possible to pass macro definitions in the same format as the `extra_m
 argument to the `Specfile.expand()` method in order to temporarily define or undefine macros
 before expression expansion.
 
-For example the following code snippet will print expanded value of the `Release` tag
+For example, the following code snippet will print the expanded value of the `Release` tag
 without system dist tag:
 
 ```python