Add some documentation

PSScriptTools/ScriptTools.ps1

@@ -28,8 +28,8 @@ Function Test-CommandExists {
         Example of how to run the script.
 
     .LINK
-        Links to further documentation.
+        https://devblogs.microsoft.com/scripting/use-a-powershell-function-to-see-if-a-command-exists/
-
+        
     .NOTES
         Detail on what the script does, if this is needed.
 
@@ -45,10 +45,10 @@ Function Test-CommandExists {
             Return $true
         }
     }
-    catch {
+    Catch {
         Return $false
     }
-    finally {
+    Finally {
         $ErrorActionPreference = $OldPreference
     }
 }