Add missing end %% to a REPO reference

mysql/README.md

@@ -118,7 +118,7 @@ If there is no database initialized when the container starts, then a default da
 
 ## Usage against an existing database
 
-If you start your `%%REPO` container instance with a data directory that already contains a database (specifically, a `mysql` subdirectory), the `$MYSQL_ROOT_PASSWORD` variable should be omitted from the run command line; it will in any case be ignored, and the pre-existing database will not be changed in any way.
+If you start your `mysql` container instance with a data directory that already contains a database (specifically, a `mysql` subdirectory), the `$MYSQL_ROOT_PASSWORD` variable should be omitted from the run command line; it will in any case be ignored, and the pre-existing database will not be changed in any way.
 
 # Supported Docker versions
 

mysql/content.md

@@ -110,4 +110,4 @@ If there is no database initialized when the container starts, then a default da
 
 ## Usage against an existing database
 
-If you start your `%%REPO` container instance with a data directory that already contains a database (specifically, a `mysql` subdirectory), the `$MYSQL_ROOT_PASSWORD` variable should be omitted from the run command line; it will in any case be ignored, and the pre-existing database will not be changed in any way.
+If you start your `%%REPO%%` container instance with a data directory that already contains a database (specifically, a `mysql` subdirectory), the `$MYSQL_ROOT_PASSWORD` variable should be omitted from the run command line; it will in any case be ignored, and the pre-existing database will not be changed in any way.