Correct "inplace" with "in-place" (GH-10480)

(cherry picked from commit f4efa312d14bc792f59514c5696e29041e05deca)

Co-authored-by: Andre Delfino <adelfino@gmail.com>
diff --git a/Doc/library/operator.rst b/Doc/library/operator.rst
index e4d6d05..11152f6 100644
--- a/Doc/library/operator.rst
+++ b/Doc/library/operator.rst
@@ -438,8 +438,8 @@
 | Ordering              | ``a > b``               | ``gt(a, b)``                          |
 +-----------------------+-------------------------+---------------------------------------+
 
-Inplace Operators
------------------
+In-place Operators
+------------------
 
 Many operations have an "in-place" version.  Listed below are functions
 providing a more primitive access to in-place operators than the usual syntax
@@ -462,7 +462,7 @@
 >>> a
 'hello'
 
-For mutable targets such as lists and dictionaries, the inplace method
+For mutable targets such as lists and dictionaries, the in-place method
 will perform the update, so no subsequent assignment is necessary:
 
 >>> s = ['h', 'e', 'l', 'l', 'o']