(PowerShellGH-812) Update folder for DSC style scripts

Previously the code folding was not tested against DSC configuration scripts.
This commit;

* Adds tests for a sample DSC script to ensure the folding occurs at the correct
  places
* Adds an AST visitor for the ParamBlockAST object.  This typically spans
  multiple lines.  This commit also adds tests for this scenario

Author: glennsarti

src/PowerShellEditorServices/Language/FindFoldsVisitor.cs

@@ -69,6 +69,12 @@ public override AstVisitAction VisitHashtable(HashtableAst objAst)
             return AstVisitAction.Continue;
         }
 
+        public override AstVisitAction VisitParamBlock(ParamBlockAst objAst)
+        {
+            if (IsValidFoldingExtent(objAst.Extent)) { this.FoldableRegions.Add(CreateFoldingReference(objAst.Extent, RegionKindNone)); }
+            return AstVisitAction.Continue;
+        }
+
         public override AstVisitAction VisitStatementBlock(StatementBlockAst objAst)
         {
             // These parent visitors will get this AST Object.  No need to process it

test/PowerShellEditorServices.Test/Language/TokenOperationsTests.cs

@@ -246,5 +246,58 @@ public void LaguageServiceFindsFoldablRegionsWithSameEndToken() {
 
             AssertFoldingReferenceArrays(expectedFolds, result);
         }
+
+        // This tests DSC style keywords and param blocks
+        [Fact]
+        public void LaguageServiceFindsFoldablRegionsWithDSC() {
+            string testString =
+@"Configuration Example
+{
+    param
+    (
+        [Parameter()]
+        [System.String[]]
+        $NodeName = 'localhost',
+
+        [Parameter(Mandatory = $true)]
+        [ValidateNotNullorEmpty()]
+        [System.Management.Automation.PSCredential]
+        $Credential
+    )
+
+    Import-DscResource -Module ActiveDirectoryCSDsc
+
+    Node $AllNodes.NodeName
+    {
+        WindowsFeature ADCS-Cert-Authority
+        {
+            Ensure = 'Present'
+            Name   = 'ADCS-Cert-Authority'
+        }
+
+        AdcsCertificationAuthority CertificateAuthority
+        {
+            IsSingleInstance = 'Yes'
+            Ensure           = 'Present'
+            Credential       = $Credential
+            CAType           = 'EnterpriseRootCA'
+            DependsOn        = '[WindowsFeature]ADCS-Cert-Authority'
+        }
+    }
+}
+";
+            FoldingReference[] expectedFolds = {
+                CreateFoldingReference(1,  0, 32, 1, null),
+                CreateFoldingReference(2,  4, 11, 5, null),
+                CreateFoldingReference(17, 4, 31, 5, null),
+                CreateFoldingReference(19, 8, 21, 9, null),
+                CreateFoldingReference(25, 8, 30, 9, null)
+            };
+
+            FoldingReference[] result = GetRegions(testString);
+
+            AssertFoldingReferenceArrays(expectedFolds, result);
+        }
+
     }
 }