DOC: satisfy codechecks (#26180)

Author: jreback

doc/source/reference/groupby.rst

@@ -58,8 +58,6 @@ Computations / Descriptive Stats
    GroupBy.first
    GroupBy.head
    GroupBy.last
-   GroupBy.idxmax
-   GroupBy.idxmin
    GroupBy.max
    GroupBy.mean
    GroupBy.median

doc/source/whatsnew/v0.25.0.rst

@@ -117,7 +117,7 @@ Concatenating Sparse Values
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 When passed DataFrames whose values are sparse, :func:`concat` will now return a
-:class:`Series` or :class:`DataFrame` with sparse values, rather than a :class`SparseDataFrame` (:issue:`25702`).
+:class:`Series` or :class:`DataFrame` with sparse values, rather than a :class:`SparseDataFrame` (:issue:`25702`).
 
 .. ipython:: python