Add links to DynamicTypes from intro pages (#1116)

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> [!IMPORTANT]
> Adds links to Dynamic Types documentation in `supported-types.mdx` for
`enum` and `class` sections.
> 
>   - **Documentation**:
> - Adds links to [Dynamic Types](/docs/calling-baml/dynamic-types) in
`supported-types.mdx` under `enum` and `class` sections.
> - Provides guidance for adding new variants to `enum` and fields to
`class` dynamically.
> 
> <sup>This description was created by </sup>[<img alt="Ellipsis"
src="https://img.shields.io/badge/Ellipsis-blue?color=175173">](https://www.ellipsis.dev?ref=BoundaryML%2Fbaml&utm_source=github&utm_medium=referral)<sup>
for 1119858. It will automatically
update as commits are pushed.</sup>

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docs/docs/snippets/supported-types.mdx

@@ -255,6 +255,9 @@ enum Name {
 }
 ```
 
+If you need to add new variants, because they need to be loaded from a file or fetched dynamically
+from a database, you can do this with [Dynamic Types](/docs/calling-baml/dynamic-types).
+
 ### class
 
 **See also:** [Class](/docs/snippets/class)
@@ -273,6 +276,9 @@ class Car {
 }
 ```
 
+If you need to add fields to a class because some properties of your class are only
+known at runtime, you can do this with [Dynamic Types](/docs/calling-baml/dynamic-types).
+
 ### Optional (?)
 
 A type that represents a value that might or might not be present.