Moving adapter behavior changes (#6151)

## What are you changing in this pull request and why?

To reduce the risk of the behavior changes page becoming unwieldy, we're
moving the adapter-specific behavior changes to their own folder, so
each adapter's change will have its own page.

This is light on content now, with only a single adapter, but it is
expected to grow quickly.

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guide](https://github.com/dbt-labs/docs.getdbt.com/blob/current/contributing/content-style-guide.md)
so my content adheres to these guidelines.
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have versioned it according to the [version a whole
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- [ ] I have added checklist item(s) to this list for anything anything
that needs to happen before this PR is merged, such as "needs technical
review" or "change base branch."
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---------

Co-authored-by: Ly Nguyen <[email protected]>
Co-authored-by: Leona B. Campbell <[email protected]>

website/docs/reference/global-configs/adapter-behavior-changes.md

@@ -0,0 +1,23 @@
+---
+title: "About adapter-specific behavior changes"
+id: "adapter-behavior-changes"
+sidebar_label: "Adapter behavior changes"
+description: "Adapter-specific behavior changes"
+hide_table_of_contents: true
+pagination_next: null
+pagination_prev: null
+---
+
+
+Some adapters can display behavior changes when certain flags are enabled. The following sections contain details about these adapter-specific behavior changes. 
+
+
+<div className="grid--3-col">
+
+<Card
+    title="Redshift"
+    body="Behavior changes for the Amazon Redshift adapter."
+    link="reference/global-configs/redshift-changes"
+    icon="redshift"/>
+
+</div>

website/docs/reference/global-configs/behavior-changes.md

@@ -129,10 +129,3 @@ on-run-start:
 ```
 </File>
 
-## Adapter-specific behavior changes
-Some adapters may show behavior changes when certain flags are enabled. Refer to the following sections for each respective adapter.
-### [Redshift] restrict_direct_pg_catalog_access
-
-Originally, the `dbt-redshift` adapter was built on top of the `dbt-postgres` adapter and used Postgres tables for metadata access. With this flag enabled, the adapter will use the Redshift API (through the Python client) if available, or query Redshift's `information_schema` tables instead of using `pg_` tables.
-
-While we don't expect any user-noticeable behavior changes due to this change, out of caution we are gating it behind a behavior-change flag and encouraging users to test it before it becomes the default for everyone.

website/docs/reference/global-configs/redshift-changes.md

@@ -0,0 +1,11 @@
+---
+title: "Amazon Redshift adapter behavior changes"
+id: "redshift-changes"
+sidebar: "Redshift"
+---
+
+## The restrict_direct_pg_catalog_access flag
+
+Originally, the `dbt-redshift` adapter was built on top of the `dbt-postgres` adapter and used Postgres tables for metadata access. When this flag is enabled, the adapter uses the Redshift API (through the Python client) if available, or queries Redshift's `information_schema` tables instead of using the `pg_` tables.
+
+While you shouldn't notice any behavior changes due to this change, however, to be cautious dbt Labs is gating it behind a behavior-change flag and encouraging you to test it before it becoming the default.

website/sidebars.js

@@ -1095,6 +1095,14 @@ const sidebarSettings = {
           items: [
             "reference/global-configs/about-global-configs",
             "reference/global-configs/behavior-changes",
+            { type: "category",
+              label: "Adapter behavior changes",
+              link: { type: "doc", id: "reference/global-configs/adapter-behavior-changes" },
+              items: [
+                "reference/global-configs/adapter-behavior-changes",
+                "reference/global-configs/redshift-changes",
+              ],
+            },
             {
               type: "category",
               label: "Setting flags",