docs: Write documentation about filter rules

Author: sboulema

docs/filterrules.md

@@ -0,0 +1,31 @@
+# Filter rules
+
+You can customize how CodeNav shows the code items in a document by creatin filter rules.
+A filter rule consists of three parts: A code item kind, modifiers and actions.
+
+## Kind
+First select the kind of code item a rule should apply to (classs, method, namespace, etc...).
+
+## Modifiers
+Secondly select a number of modifiers to narrow down the rule.
+
+### Access
+Match code items by access (public, private, etc...)
+
+### Empty
+Match code items that do not have visible child items
+
+## Action
+Finally select then action to should be applied to the code item.
+
+### Hide
+Code item, including any child items, will not be shown
+
+### Ignore
+Code item will not be shown, but its child items will be shown
+
+### Opacity
+Code items will be shown with the selected opacity, where 0 is transparent and 100 is opaque
+
+## Notes
+- Not all modifiers and/or actions are available for each kind, the filter dialog will respond and enable the correct list of modifiers

docs/index.md

@@ -2,6 +2,9 @@
 
 Welcome to the CodeNav documentation. Browse the sections below to learn more about the extension and its development.
 
+## Filter rulwa
+Read all on how to modify the appearance of code items usin [filter rules](filterrules.md)
+
 ## Version 10
 Read all about the new [version 10](version10.md) of CodeNav