Remove deprecated dot-source reference tests (and data)

Let it be known that Patrick bets $500 that no one notices this.
And to be fair, searching the whole workspace now works great.

Author: andyleejordan

test/PowerShellEditorServices.Test.Shared/Definition/FindsDotSourcedFile.cs

@@ -5,7 +5,7 @@
 
 namespace Microsoft.PowerShell.EditorServices.Test.Shared.Definition
 {
-    public static class FindsFunctionDefinitionInDotSourceReferenceData
+    public static class FindsFunctionDefinitionInWorkspaceData
     {
         public static readonly ScriptRegion SourceDetails = new(
             file: TestUtilities.NormalizePath("References/FileWithReferences.ps1"),