#1199: Add documentation for merge behavior

packages/docs/src/docs/pattern-pseudo-patterns.md

@@ -19,6 +19,12 @@ Pseudo-patterns are similar to [pattern-specific JSON files](/docs/creating-patt
 
 The tilde (`~`) and `.json` file extension are the hints that Pattern Lab uses to determine that this is a pseudo-pattern. The `patternName` tells Pattern Lab which existing pattern it should use when rendering the pseudo-pattern. The JSON file itself works exactly like the [pattern-specific JSON file](/docs/creating-pattern-specific-values/). It has the added benefit that the pseudo-pattern will also inherit any values from the existing pattern's pattern-specific JSON file.
 
+As default arrays in pseudo-pattern data will be concatenated with the base patterns array data. To override this behavior globally you can set the parameter `patternMergeVariantArrays` in you `patternlab-config.json` to `false`.
+
+```json
+"patternMergeVariantArrays": false
+```
+
 From a navigation and naming perspective `patternName` and `pseudoPatternName` will be combined.
 
 ## Adding Pseudo-Patterns to Your Project