replace arraylist with list<string>, remove unnecessary casts and iteration

Author: h3xds1nz

src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Documents/Speller.cs

@@ -177,16 +177,15 @@ internal ITextPointer GetNextSpellingErrorPosition(ITextPointer position, Logica
         // for an error range.
         // This method actually runs the speller on the specified text,
         // re-evaluating the error from scratch.
-        internal IList GetSuggestionsForError(SpellingError error)
+        internal List<string> GetSuggestionsForError(SpellingError error)
         {
             ITextPointer contextStart;
             ITextPointer contextEnd;
             ITextPointer contentStart;
             ITextPointer contentEnd;
             TextMap textMap;
-            ArrayList suggestions;
 
-            suggestions = new ArrayList(1);
+            List<string> suggestions = new();
 
             //
             // IMPORTANT!!
@@ -915,7 +914,7 @@ private bool ScanErrorTextSegment(SpellerInteropBase.ISpellerSegment textSegment
             {
                 if (textSegment.SubSegments.Count == 0)
                 {
-                    ArrayList suggestions = (ArrayList)data.Data;
+                    List<string> suggestions = (List<string>)data.Data;
                     if(textSegment.Suggestions.Count > 0)
                     {
                         foreach(string suggestion in textSegment.Suggestions)

src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Documents/SpellerError.cs

@@ -94,15 +94,7 @@ public void IgnoreAll()
         /// </remarks>
         public IEnumerable<string> Suggestions
         {
-            get
-            {
-                IList suggestions = _speller.GetSuggestionsForError(this);
-
-                for (int i=0; i<suggestions.Count; i++)
-                {
-                    yield return (string)suggestions[i];
-                }
-            }
+            get => _speller.GetSuggestionsForError(this);
         }
 
         #endregion Public Properties