Encode cursor hotspots into GIF comments

rsrc/graphics.exd/mac/cursors/READ_BEFORE_EDITING.txt

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+When editing the GIF files in this folder, you need to be aware how the hotspot is stored.
+Each of these GIF files encodes the cursor's hotspot into a GIF comment with the following
+syntax (case-sensitive):
+
+	Hotspot(x,y)
+
+where x and y are substituted with the actual integer coordinates. There should be no extra
+spaces anywhere in that. (However, anything after the closing parenthesis will be ignored.)
+
+If you edit any of these images, be sure to update the hotspot if necessary!