Add "go/south+meaning" (cheat.sh#332)

sheets/_go/south meaning

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+go south
+
+## Etymology
+
+(become worse): The origin is unclear. Common belief attributes it to the
+standard orientation of maps, where south is the downwards direction.
+Alternatively, it could stem from a euphemism used by some Native Americans for
+dying.
+
+## Meaning
+
+1. (idiomatic) To become unfavorable; to decrease; to take a turn for the worse.
+2. To make an escape; to disappear.
+3. (slang) To give somebody oral sex.
+