Fix documentation issues (#10306)

This PR addresses some issues that were causing documentation builds to fail. Namely:

1. Changing all `Example` headers to `Examples` (`Examples` is correct, `Example` is incorrect. see: https://numpydoc.readthedocs.io/en/latest/format.html#examples)
2. Ensuring all headers have correct underline length

Authors:
  - AJ Schmidt (https://github.com/ajschmidt8)

Approvers:
  - GALI PREM SAGAR (https://github.com/galipremsagar)

URL: #10306

python/cudf/cudf/core/series.py

@@ -3857,8 +3857,8 @@ def is_leap_year(self):
         Series
         Booleans indicating if dates belong to a leap year.
 
-        Example
-        -------
+        Examples
+        --------
         >>> import pandas as pd, cudf
         >>> s = cudf.Series(
         ...     pd.date_range(start='2000-02-01', end='2013-02-01', freq='1Y'))
@@ -3915,7 +3915,7 @@ def quarter(self):
         Integer indicating which quarter the date belongs to.
 
         Examples
-        -------
+        --------
         >>> import cudf
         >>> s = cudf.Series(["2020-05-31 08:00:00","1999-12-31 18:40:00"],
         ...     dtype="datetime64[ms]")
@@ -3991,8 +3991,8 @@ def days_in_month(self):
         Series
         Integers representing the number of days in month
 
-        Example
-        -------
+        Examples
+        --------
         >>> import pandas as pd, cudf
         >>> s = cudf.Series(
         ...     pd.date_range(start='2000-08-01', end='2001-08-01', freq='1M'))
@@ -4042,8 +4042,8 @@ def is_month_end(self):
         Series
         Booleans indicating if dates are the last day of the month.
 
-        Example
-        -------
+        Examples
+        --------
         >>> import pandas as pd, cudf
         >>> s = cudf.Series(
         ...     pd.date_range(start='2000-08-26', end='2000-09-03', freq='1D'))
@@ -4088,8 +4088,8 @@ def is_quarter_start(self):
         Series
         Booleans indicating if dates are the begining of a quarter
 
-        Example
-        -------
+        Examples
+        --------
         >>> import pandas as pd, cudf
         >>> s = cudf.Series(
         ...     pd.date_range(start='2000-09-26', end='2000-10-03', freq='1D'))
@@ -4134,8 +4134,8 @@ def is_quarter_end(self):
         Series
         Booleans indicating if dates are the end of a quarter
 
-        Example
-        -------
+        Examples
+        --------
         >>> import pandas as pd, cudf
         >>> s = cudf.Series(
         ...     pd.date_range(start='2000-09-26', end='2000-10-03', freq='1D'))
@@ -4182,8 +4182,8 @@ def is_year_start(self):
         Series
         Booleans indicating if dates are the first day of the year.
 
-        Example
-        -------
+        Examples
+        --------
         >>> import pandas as pd, cudf
         >>> s = cudf.Series(pd.date_range("2017-12-30", periods=3))
         >>> dates
@@ -4216,8 +4216,8 @@ def is_year_end(self):
         Series
         Booleans indicating if dates are the last day of the year.
 
-        Example
-        -------
+        Examples
+        --------
         >>> import pandas as pd, cudf
         >>> dates = cudf.Series(pd.date_range("2017-12-30", periods=3))
         >>> dates

python/cudf/cudf/core/window/rolling.py

@@ -302,8 +302,8 @@ def apply(self, func, *args, **kwargs):
         -----
         See notes of the :meth:`cudf.Series.applymap`
 
-        Example
-        -------
+        Examples
+        --------
 
         >>> import cudf
         >>> def count_if_gt_3(window):