DOC: fix examples in Timestamp functions (#44702)

* DOC: fix examples in Timestamp functions

`Timestamp.utcfromtimestamp()` and `Timestamp.fromtimestamp()`

* DOC: fix examples in Timestamp functions

`Timestamp.utcfromtimestamp()` and `Timestamp.fromtimestamp()`

Author: valentinoli

pandas/_libs/tslibs/nattype.pyx

@@ -553,7 +553,7 @@ class NaTType(_NaT):
 
         Examples
         --------
-        >>> pd.Timestamp.fromtimestamp(1584199972)
+        >>> pd.Timestamp.utcfromtimestamp(1584199972)
         Timestamp('2020-03-14 15:32:52')
         """,
     )
@@ -566,7 +566,7 @@ class NaTType(_NaT):
 
         Examples
         --------
-        >>> pd.Timestamp.utcfromtimestamp(1584199972)
+        >>> pd.Timestamp.fromtimestamp(1584199972)
         Timestamp('2020-03-14 15:32:52')
 
         Note that the output may change depending on your local time.

pandas/_libs/tslibs/timestamps.pyx

@@ -1162,7 +1162,7 @@ class Timestamp(_Timestamp):
 
         Examples
         --------
-        >>> pd.Timestamp.fromtimestamp(1584199972)
+        >>> pd.Timestamp.utcfromtimestamp(1584199972)
         Timestamp('2020-03-14 15:32:52')
         """
         return cls(datetime.utcfromtimestamp(ts))
@@ -1176,7 +1176,7 @@ class Timestamp(_Timestamp):
 
         Examples
         --------
-        >>> pd.Timestamp.utcfromtimestamp(1584199972)
+        >>> pd.Timestamp.fromtimestamp(1584199972)
         Timestamp('2020-03-14 15:32:52')
 
         Note that the output may change depending on your local time.