Add visualization and renderer documentation

src/documentation/visualizations/about_rendering.malloynb

@@ -1,25 +1,24 @@
 >>>markdown
-# Rendering Documentation
-The latest and most up to date documentation for the Malloy renderer are now found in GitHub:
+# Rendering Results
 
-- [Renderer Tag Documentation](https://github.com/malloydata/malloy/blob/main/packages/malloy-render/docs/renderer_tags_overview.md)
-- [Renderer Tag Cheatsheet](https://github.com/malloydata/malloy/blob/main/packages/malloy-render/docs/renderer_tag_cheatsheet.md)
+Malloy's rendering library interprets tags to control how query results are displayed.
 
-For developers wishing to implement custom renderers, a plugin system is available:
-- [Plugin System Overview](https://github.com/malloydata/malloy/blob/main/packages/malloy-render/docs/plugin-system.md)
-- [Plugin Quick Start](https://github.com/malloydata/malloy/blob/main/packages/malloy-render/docs/plugin-quick-start.md)
-- [Plugin API Reference](https://github.com/malloydata/malloy/blob/main/packages/malloy-render/docs/plugin-api-reference.md)
->>>markdown
- # Using Render Tags
+## Documentation
+
+- [Renderer Tags](renderer_tags.malloynb) - Complete guide to all visualization and formatting tags
+- [Tag Cheatsheet](renderer_cheatsheet.malloynb) - Quick reference for all tags
+
+## Plugin System
 
-When Malloy runs a query, it returns two things.  The *results* of the query and *metadata* about the results.  The metadata are the schema for the results, including type information.  Malloy also provides a mechanism to tag things in the source code and return tags with this meta data. 
+- [Custom Plugins](plugins.malloynb) - Build your own renderers for specialized visualizations
 
-In Malloy, anything that can be named can be tagged. A tag starts with a `#`. Tags that start on a new line attach the tag the thing on the following line. For more details about how tagging works, see the [Tags](../language/tags.malloynb) section.
+---
 
-Malloy's rendering library interprets these tags to change how results are rendered. 
+## How Tags Work
 
-## Tagging individual elements
-In the query below, the measure `percent_of_total` is tagged as a percentage. Any time `percent_of_total` is used in a query, Malloy's rendering library will be displayed as a percentage.
+When Malloy runs a query, it returns results and metadata including schema and tags. Tags start with `#` and attach to the following item.
+
+For details on tag syntax, see [Tags](../language/tags.malloynb).
 >>>malloy
 source: flights is duckdb.table('../data/flights.parquet') extend {
   measure:
@@ -31,23 +30,18 @@ source: flights is duckdb.table('../data/flights.parquet') extend {
 #(docs) size=small limit=5000
 run: flights -> {
   group_by: carrier
-  aggregate: 
-    flight_count 
+  aggregate:
+    flight_count
     percent_of_flights
 }
->>>malloy
-#(docs) size=small limit=5000
-run: duckdb.table('../data/flights.parquet') ->  {
-  group_by: carrier
-  aggregate: flight_count is count()
-}
 >>>markdown
 
-Simply adding `# bar_chart` before the query tags it and tells the rendering library to show the result as a bar chart. See the docs on the [Bar Chart tag](./bar_charts.malloynb) for more information.
+## Quick Examples
 >>>malloy
 #(docs) size=large limit=5000
 # bar_chart
-run: duckdb.table('../data/flights.parquet') ->  {
+run: duckdb.table('../data/flights.parquet') -> {
   group_by: carrier
   aggregate: flight_count is count()
-}
+  limit: 10
+}

src/documentation/visualizations/plugins.malloynb

@@ -0,0 +1,46 @@
+>>>markdown
+# Custom Renderer Plugins
+
+The Malloy Render plugin system lets you create custom visualizations for specific field types or data patterns.
+
+## Use Cases
+
+- Custom chart types not included in the standard renderer
+- Domain-specific visualizations (maps, diagrams, etc.)
+- Branded or styled components
+- Interactive visualizations with custom behavior
+
+## Getting Started
+
+Plugins can be built using SolidJS (recommended) or direct DOM manipulation. They match fields based on tags and field types.
+
+```typescript
+const MyPluginFactory: RenderPluginFactory = {
+  name: 'my_plugin',
+
+  matches: (field, fieldTag, fieldType) => fieldTag.has('my_plugin'),
+
+  create: (field) => ({
+    name: 'my_plugin',
+    field,
+    renderMode: 'solidjs',
+    sizingStrategy: 'fixed',
+    renderComponent: (props) => <div>{props.dataColumn.value}</div>,
+    getMetadata: () => ({ type: 'my_plugin' })
+  })
+};
+```
+
+Then tag fields in Malloy to use your plugin:
+
+```malloy
+source: data extend {
+  dimension: status # my_plugin
+}
+```
+
+## Documentation
+
+- [Plugin System Overview](https://github.com/malloydata/malloy/blob/main/packages/malloy-render/docs/plugin-system.md) - Architecture and concepts
+- [Plugin Quick Start](https://github.com/malloydata/malloy/blob/main/packages/malloy-render/docs/plugin-quick-start.md) - Minimal examples
+- [Plugin API Reference](https://github.com/malloydata/malloy/blob/main/packages/malloy-render/docs/plugin-api-reference.md) - Complete type definitions