Fix remaining converters: Remove unnecessary Task.Run from DocxConverter, XlsxConverter, and PptxConverter

Co-authored-by: KSemenenko <4385716+KSemenenko@users.noreply.github.com>

Author: Copilot

src/MarkItDown/Converters/DocxConverter.cs

@@ -89,22 +89,19 @@ public async Task<DocumentConverterResult> ConvertAsync(Stream stream, StreamInf
         }
     }
 
-    private static async Task<string> ExtractTextFromDocxAsync(Stream stream, CancellationToken cancellationToken)
+    private static Task<string> ExtractTextFromDocxAsync(Stream stream, CancellationToken cancellationToken)
     {
         var result = new StringBuilder();
 
-        await Task.Run(() =>
-        {
-            using var wordDocument = WordprocessingDocument.Open(stream, false);
-            var body = wordDocument.MainDocumentPart?.Document?.Body;
+        using var wordDocument = WordprocessingDocument.Open(stream, false);
+        var body = wordDocument.MainDocumentPart?.Document?.Body;
 
-            if (body != null)
-            {
-                ProcessBodyElements(body, result, cancellationToken);
-            }
-        }, cancellationToken);
+        if (body != null)
+        {
+            ProcessBodyElements(body, result, cancellationToken);
+        }
 
-        return result.ToString().Trim();
+        return Task.FromResult(result.ToString().Trim());
     }
 
     private static void ProcessBodyElements(Body body, StringBuilder result, CancellationToken cancellationToken)

src/MarkItDown/Converters/PptxConverter.cs

@@ -91,31 +91,28 @@ public async Task<DocumentConverterResult> ConvertAsync(Stream stream, StreamInf
         }
     }
 
-    private static async Task<string> ExtractContentFromPptxAsync(Stream stream, CancellationToken cancellationToken)
+    private static Task<string> ExtractContentFromPptxAsync(Stream stream, CancellationToken cancellationToken)
     {
         var result = new StringBuilder();
 
-        await Task.Run(() =>
+        using var presentationDocument = PresentationDocument.Open(stream, false);
+        var presentationPart = presentationDocument.PresentationPart;
+        
+        if (presentationPart?.Presentation?.SlideIdList != null)
         {
-            using var presentationDocument = PresentationDocument.Open(stream, false);
-            var presentationPart = presentationDocument.PresentationPart;
+            var slideCount = 0;
 
-            if (presentationPart?.Presentation?.SlideIdList != null)
+            foreach (var slideId in presentationPart.Presentation.SlideIdList.Elements<SlideId>())
             {
-                var slideCount = 0;
+                cancellationToken.ThrowIfCancellationRequested();
 
-                foreach (var slideId in presentationPart.Presentation.SlideIdList.Elements<SlideId>())
-                {
-                    cancellationToken.ThrowIfCancellationRequested();
-                    
-                    slideCount++;
-                    var slidePart = (SlidePart)presentationPart.GetPartById(slideId.RelationshipId!);
-                    ProcessSlide(slidePart, slideCount, result);
-                }
+                slideCount++;
+                var slidePart = (SlidePart)presentationPart.GetPartById(slideId.RelationshipId!);
+                ProcessSlide(slidePart, slideCount, result);
             }
-        }, cancellationToken);
+        }
 
-        return result.ToString().Trim();
+        return Task.FromResult(result.ToString().Trim());
     }
 
     private static void ProcessSlide(SlidePart slidePart, int slideNumber, StringBuilder result)

src/MarkItDown/Converters/XlsxConverter.cs

@@ -89,28 +89,25 @@ public async Task<DocumentConverterResult> ConvertAsync(Stream stream, StreamInf
         }
     }
 
-    private static async Task<string> ExtractDataFromXlsxAsync(Stream stream, CancellationToken cancellationToken)
+    private static Task<string> ExtractDataFromXlsxAsync(Stream stream, CancellationToken cancellationToken)
     {
         var result = new StringBuilder();
 
-        await Task.Run(() =>
+        using var spreadsheetDocument = SpreadsheetDocument.Open(stream, false);
+        var workbookPart = spreadsheetDocument.WorkbookPart;
+        
+        if (workbookPart?.Workbook?.Sheets != null)
         {
-            using var spreadsheetDocument = SpreadsheetDocument.Open(stream, false);
-            var workbookPart = spreadsheetDocument.WorkbookPart;
-            
-            if (workbookPart?.Workbook?.Sheets != null)
+            foreach (var sheet in workbookPart.Workbook.Sheets.Elements<Sheet>())
             {
-                foreach (var sheet in workbookPart.Workbook.Sheets.Elements<Sheet>())
-                {
-                    cancellationToken.ThrowIfCancellationRequested();
-                    
-                    var worksheetPart = (WorksheetPart)workbookPart.GetPartById(sheet.Id!);
-                    ProcessWorksheet(worksheetPart, sheet.Name?.Value ?? "Sheet", result, workbookPart);
-                }
+                cancellationToken.ThrowIfCancellationRequested();
+                
+                var worksheetPart = (WorksheetPart)workbookPart.GetPartById(sheet.Id!);
+                ProcessWorksheet(worksheetPart, sheet.Name?.Value ?? "Sheet", result, workbookPart);
             }
-        }, cancellationToken);
+        }
 
-        return result.ToString().Trim();
+        return Task.FromResult(result.ToString().Trim());
     }
 
     private static void ProcessWorksheet(WorksheetPart worksheetPart, string sheetName, StringBuilder result, WorkbookPart workbookPart)