gh-112043: Align concurrent.futures.Executor.map docs with implementation (#114153)

The first parameter is named 'fn', not 'func'.

Author: erlend-aasland

Doc/library/concurrent.futures.rst

@@ -39,22 +39,22 @@ Executor Objects
              future = executor.submit(pow, 323, 1235)
              print(future.result())
 
-   .. method:: map(func, *iterables, timeout=None, chunksize=1)
+   .. method:: map(fn, *iterables, timeout=None, chunksize=1)
 
-      Similar to :func:`map(func, *iterables) <map>` except:
+      Similar to :func:`map(fn, *iterables) <map>` except:
 
       * the *iterables* are collected immediately rather than lazily;
 
-      * *func* is executed asynchronously and several calls to
-        *func* may be made concurrently.
+      * *fn* is executed asynchronously and several calls to
+        *fn* may be made concurrently.
 
       The returned iterator raises a :exc:`TimeoutError`
       if :meth:`~iterator.__next__` is called and the result isn't available
       after *timeout* seconds from the original call to :meth:`Executor.map`.
       *timeout* can be an int or a float.  If *timeout* is not specified or
       ``None``, there is no limit to the wait time.
 
-      If a *func* call raises an exception, then that exception will be
+      If a *fn* call raises an exception, then that exception will be
       raised when its value is retrieved from the iterator.
 
       When using :class:`ProcessPoolExecutor`, this method chops *iterables*