Clarify global.json version support (dotnet#49941)

* Clarify global.json version support and update SDK availability notes

* update wording

* Update docs/core/tools/global-json.md

Co-authored-by: Copilot <[email protected]>

* Clarify global.json version support

---------

Co-authored-by: Copilot <[email protected]>

Author: meaghanlewis

docs/core/tools/global-json.md

@@ -43,7 +43,9 @@ The version of the .NET SDK to use.
 
 This field:
 
-- Doesn't have wildcard support; that is, you must specify the full version number.
+- Requires the full version number, such as 9.0.100.
+- Doesn't support version numbers like 9, 9.0, or 9.0.x.
+- Doesn't have wildcard support.
 - Doesn't support version ranges.
 
 #### `allowPrerelease`
@@ -90,7 +92,7 @@ The following table shows the possible values for the `rollForward` key:
 #### `paths`
 
 - Type: Array of `string`
-- Available since: .NET 10 Preview 3 SDK.
+- Available since: .NET 10 SDK.
 
 Specifies the locations that should be considered when searching for a compatible .NET SDK. Paths can be absolute or relative to the location of the *global.json* file. The special value `$host$` represents the location corresponding to the running `dotnet` executable.
 
@@ -103,7 +105,7 @@ This feature enables using local SDK installations (such as SDKs relative to a r
 #### `errorMessage`
 
 - Type: `string`
-- Available since: .NET 10 Preview 3 SDK.
+- Available since: .NET 10 SDK.
 
 Specifies a custom error message displayed when the SDK resolver can't find a compatible .NET SDK.
 
@@ -209,6 +211,17 @@ The following example shows how to specify additional SDK search paths and a cus
 }
 ```
 
+The following example shows an invalid version specified. The output of the command `dotnet --info` shows the error message: "Version '10.0' is not valid for the 'sdk/version' value."
+
+```json
+{
+  "sdk": {
+    "version": "10.0",
+    "rollForward": "latestFeature"
+  }
+}
+```
+
 The following example shows how to specify `Microsoft.Testing.Platform` as the test runner:
 
 ```json