fix typo

Author: Mattias Schlenker

src/onprem/en/devel_check_plugins.asciidoc

@@ -2101,7 +2101,7 @@ You can now produce debug output depending on the value of the debug object:
 ====
 The debug object will change its path between {CMK} {v23} and {v24}.
 Instead of the current location `cmk.utils`, it will be found in `cmk.ccc`.
-Portable code first attempts to import from the new path to fall back to the old path case of an error.
+Portable code first attempts to import from the new path to fall back to the old path in case of an error.
 ====
 
 [{python}]