Add explanations about the ! prefix in ignore files (v1.6.20)

.cursorignore

@@ -1,5 +1,8 @@
 # Cursor ignore file
 # Additional patterns beyond .gitignore for Cursor's AI context
 
+# You can use the ! prefix to include files that are excluded by .gitignore
+# Example: !important-file.log (This would include important-file.log even if *.log is in .gitignore)
+
 # Cursor-specific temporary files
 .cursor-tmp/