DOC: typo in v0.10 whatsnew

Author: Ka Wo Chen <[email protected]>

Closes #12122 from kawochen/DOC-1_10-whatsnew-typo and squashes the following commits:

a7a165b [Ka Wo Chen] DOC: typo in v1.10 whatsnew

Author: kawochen

doc/source/whatsnew/v0.10.0.txt

@@ -82,7 +82,7 @@ Note:
     series.resample('D', how='sum', closed='right', label='right')
 
 - Infinity and negative infinity are no longer treated as NA by ``isnull`` and
-  ``notnull``. That they every were was a relic of early pandas. This behavior
+  ``notnull``. That they ever were was a relic of early pandas. This behavior
   can be re-enabled globally by the ``mode.use_inf_as_null`` option:
 
 .. ipython:: python