DOC: Corrected typo in warning on coerce (#56699)

* Corrected typo in warning on coerce

* Correct typo in v2.1.0.rst as well

Author: aaron-robeson-8451

doc/source/whatsnew/v2.1.0.rst

@@ -432,7 +432,7 @@ In a future version, these will raise an error and you should cast to a common d
 
   In [3]: ser[0] = 'not an int64'
   FutureWarning:
-    Setting an item of incompatible dtype is deprecated and will raise in a future error of pandas.
+    Setting an item of incompatible dtype is deprecated and will raise an error in a future version of pandas.
     Value 'not an int64' has dtype incompatible with int64, please explicitly cast to a compatible dtype first.
 
   In [4]: ser

pandas/core/internals/blocks.py

@@ -512,7 +512,7 @@ def coerce_to_target_dtype(self, other, warn_on_upcast: bool = False) -> Block:
         if warn_on_upcast:
             warnings.warn(
                 f"Setting an item of incompatible dtype is deprecated "
-                "and will raise in a future error of pandas. "
+                "and will raise an error in a future version of pandas. "
                 f"Value '{other}' has dtype incompatible with {self.values.dtype}, "
                 "please explicitly cast to a compatible dtype first.",
                 FutureWarning,