mode takes an array not a single value

docs/source/370_irreversible.rst

@@ -17,14 +17,14 @@ Mode select is implemented through a table with a ``mode`` field that specifies
     setenv{
         name = "MY_VAR",
         value = "some_value",
-        mode = "load"
+        mode = {"load"}
     }
 
     -- Execute only during unload
     setenv{
         name = "CLEANUP_VAR", 
         value = "cleanup_value",
-        mode = "unload"
+        mode = {"unload"}
     }
 
 Supported Modes
@@ -40,8 +40,8 @@ Important Notes
 
 1. When using mode select, the specified action becomes irreversible in the opposite mode. For example:
 
-   * If an action is specified with ``mode = "load"``, it will not be automatically reversed during unload
-   * If an action is specified with ``mode = "unload"``, it will not be automatically reversed during load
+   * If an action is specified with ``mode = {"load"}``, it will not be automatically reversed during unload
+   * If an action is specified with ``mode = {"unload"}``, it will not be automatically reversed during load
 
 2. To completely remove the effects of a mode-specific module, you may need to:
 
@@ -67,7 +67,7 @@ Consider a module that needs to perform special cleanup during unload::
     setenv{
         name = "CLEANUP_REQUIRED",
         value = "true",
-        mode = "unload"
+        mode = {"unload"}
     }
 
 In this example:
@@ -83,4 +83,4 @@ Best Practices
 2. Document any irreversible changes in the module's help text
 3. Consider providing helper functions or instructions for users to manually reverse changes
 4. Test both load and unload scenarios thoroughly
-5. Consider the impact on module collections and module restore operations 
+5. Consider the impact on module collections and module restore operations