Fix codefence in examples (#2881)

Author: fflaten

src/functions/assert/Equivalence/Should-BeEquivalent.ps1

@@ -650,7 +650,7 @@ function Should-BeEquivalent {
     This example generates an equivalency option object that excludes the 'Id' and 'Timestamp' properties from the comparison and uses a simple equality comparison strategy.
 
     .EXAMPLE
-    ```powereshell
+    ```powershell
     Should-BeEquivalent ... -ExcludePathsNotOnExpected
     ```
 

src/functions/assert/String/Should-BeEmptyString.ps1

@@ -29,7 +29,7 @@
     This test will fail, the input is not an empty string.
 
     .EXAMPLE
-    ```
+    ```powershell
     $null | Should-BeEmptyString
     @() | Should-BeEmptyString
     $() | Should-BeEmptyString

src/functions/assert/String/Should-NotBeWhiteSpaceString.ps1

@@ -29,7 +29,7 @@
     This test will fail, the input is a whitespace only string.
 
     .EXAMPLE
-    ```
+    ```powershell
     $null | Should-NotBeWhiteSpaceString
     "" | Should-NotBeWhiteSpaceString
     $() | Should-NotBeWhiteSpaceString