Add absolute value to head() and tail() docstrings for negative values of n (pandas-dev#47195)

* add absolute value to head and tail docstrings

* remove minus sign because n is already negative

Author: jackgoldsmith4

pandas/core/generic.py

@@ -5182,7 +5182,7 @@ def head(self: NDFrameT, n: int = 5) -> NDFrameT:
         has the right type of data in it.
 
         For negative values of `n`, this function returns all rows except
-        the last `n` rows, equivalent to ``df[:-n]``.
+        the last `|n|` rows, equivalent to ``df[:n]``.
 
         If n is larger than the number of rows, this function returns all rows.
 
@@ -5257,7 +5257,7 @@ def tail(self: NDFrameT, n: int = 5) -> NDFrameT:
         after sorting or appending rows.
 
         For negative values of `n`, this function returns all rows except
-        the first `n` rows, equivalent to ``df[n:]``.
+        the first `|n|` rows, equivalent to ``df[|n|:]``.
 
         If n is larger than the number of rows, this function returns all rows.