MANIFEST.in: add missing word in comment

MANIFEST.in

@@ -4,7 +4,7 @@
 # This only includes a bare minimum of files required for local installation (and PyPI upload).
 # Note: If setuptools-scm is installed, it will include all files checked into version control, and it is not currently possible to opt out (setuptools_scm/issues/190)
 
-# license files are already included pyproject.toml
+# license files are already included through pyproject.toml
 recursive-include sourcebuild/patches/ *
 recursive-include src *.py
 recursive-include setupsrc *.py