Implemented the text element rename function

I18N Commander/Processor/TextElementProcessor.cs

@@ -57,4 +57,34 @@ public static class TextElementProcessor
             return updateException.ToProcessorResult<TextElement>();
         }
     }
+    
+    // Renames a text element:
+    public static async Task<ProcessorResult<TextElement>> RenameTextElement(int id, string newName)
+    {
+        await using var db = ProcessorMeta.ServiceProvider.GetRequiredService<DataContext>();
+        
+        var textElement = await db.TextElements.FirstAsync(n => n.Id == id);
+        if (textElement is null)
+            throw new ArgumentOutOfRangeException(nameof(id));
+        
+        // Get the corresponding section:
+        var section = (await db.TextElements.FirstAsync(n => n.Id == id)).Section;
+        
+        // Generate a code:
+        var code = await Utils.GenerateCode(newName, db.TextElements, (n, code) => n.Section == section && n.Code == code);
+        
+        textElement.Name = newName;
+        textElement.Code = code;
+        
+        // Save the changes:
+        try
+        {
+            await db.SaveChangesAsync();
+            return new ProcessorResult<TextElement>(textElement);
+        }
+        catch (DbUpdateException updateException)
+        {
+            return updateException.ToProcessorResult<TextElement>();
+        }
+    }
 }