fix: remove .md suffix from prebuilt workspaces docs link (#490)

The link to the prebuilt workspace documentation on coder.com included a .md suffix, causing a 404. This removes the suffix so the link resolves correctly.

Co-authored-by: blink-so[bot] <211532188+blink-so[bot]@users.noreply.github.com>

Author: blinkagent[bot]

docs/data-sources/workspace_preset.md

@@ -56,7 +56,7 @@ data "coder_workspace_preset" "standard" {
 - `description` (String) Describe what this preset does.
 - `icon` (String) A URL to an icon that will display in the dashboard. View built-in icons [here](https://github.com/coder/coder/tree/main/site/static/icon). Use a built-in icon with `"${data.coder_workspace.me.access_url}/icon/<path>"`.
 - `parameters` (Map of String) Workspace parameters that will be set by the workspace preset. For simple templates that only need prebuilds, you may define a preset with zero parameters. Because workspace parameters may change between Coder template versions, preset parameters are allowed to define values for parameters that do not exist in the current template version.
-- `prebuilds` (Block Set, Max: 1) Configuration for prebuilt workspaces associated with this preset. Coder will maintain a pool of standby workspaces based on this configuration. When a user creates a workspace using this preset, they are assigned a prebuilt workspace instead of waiting for a new one to build. See prebuilt workspace documentation [here](https://coder.com/docs/admin/templates/extending-templates/prebuilt-workspaces.md) (see [below for nested schema](#nestedblock--prebuilds))
+- `prebuilds` (Block Set, Max: 1) Configuration for prebuilt workspaces associated with this preset. Coder will maintain a pool of standby workspaces based on this configuration. When a user creates a workspace using this preset, they are assigned a prebuilt workspace instead of waiting for a new one to build. See prebuilt workspace documentation [here](https://coder.com/docs/admin/templates/extending-templates/prebuilt-workspaces) (see [below for nested schema](#nestedblock--prebuilds))
 
 ### Read-Only
 

provider/workspace_preset.go

@@ -131,7 +131,7 @@ func workspacePresetDataSource() *schema.Resource {
 			},
 			"prebuilds": {
 				Type:        schema.TypeSet,
-				Description: "Configuration for prebuilt workspaces associated with this preset. Coder will maintain a pool of standby workspaces based on this configuration. When a user creates a workspace using this preset, they are assigned a prebuilt workspace instead of waiting for a new one to build. See prebuilt workspace documentation [here](https://coder.com/docs/admin/templates/extending-templates/prebuilt-workspaces.md)",
+				Description: "Configuration for prebuilt workspaces associated with this preset. Coder will maintain a pool of standby workspaces based on this configuration. When a user creates a workspace using this preset, they are assigned a prebuilt workspace instead of waiting for a new one to build. See prebuilt workspace documentation [here](https://coder.com/docs/admin/templates/extending-templates/prebuilt-workspaces)",
 				Optional:    true,
 				MaxItems:    1,
 				Elem: &schema.Resource{