docs(screenshot): tighten ScreenshotCapturer summary

Drop the "Shared by ManageUI.render_ui ... and ScreenshotUtility's editor
synchronous-spin path" line. The first sentence already describes the class on
its own; naming specific callers in the doc is brittle (goes stale if a call
site is added or renamed) and pushed the summary to 4 content lines, over the
1-2 line guidance.

Author: KamilDev

MCPForUnity/Runtime/Helpers/ScreenshotUtility.cs

@@ -815,10 +815,8 @@ private static string GetProjectRootPath()
     }
 
     /// <summary>
-    /// Transient MonoBehaviour that captures the composited frame at end-of-frame via
-    /// ScreenCapture.CaptureScreenshotAsTexture and invokes a callback. Self-destructs.
-    /// Shared by ManageUI.render_ui (two-call pending/ready) and ScreenshotUtility's
-    /// editor synchronous-spin path.
+    /// Transient MonoBehaviour that yields WaitForEndOfFrame, calls
+    /// ScreenCapture.CaptureScreenshotAsTexture, invokes the callback, and self-destructs.
     /// </summary>
     public sealed class ScreenshotCapturer : MonoBehaviour
     {