Fix Az.MixedReality Syntax Errors (#17668)

Author: CaptainFanZzz

src/MixedReality/MixedReality/help/New-AzRemoteRenderingAccount.md

@@ -24,7 +24,7 @@ Create a new Remote Rendering Account in certain Subscription, Resource Group an
 
 ### Example 1
 ```powershell
-New-AzureRmRemoteRenderingAccount -ResourceGroup rg1 -Name example -Location centralus
+New-AzRemoteRenderingAccount -ResourceGroup rg1 -Name example -Location centralus
 ```
 
 ```output

src/MixedReality/MixedReality/help/New-AzSpatialAnchorsAccount.md

@@ -24,7 +24,7 @@ Create a new Spatial Anchors Account in certain Subscription, Resource Group and
 
 ### Example 1
 ```powershell
-New-AzureRmSpatialAnchorsAccount -ResourceGroup rg1 -Name example -Location centralus
+New-AzSpatialAnchorsAccount -ResourceGroup rg1 -Name example -Location centralus
 ```
 
 ```output