[doc] Fix erroneous backslashes in signatures and names (GH-23658)



The issue being resolved is shown in the 3.10 docs (if you select docs for older versions you won't see a visual glitch).

The newer sphinx version that produces the 3.10 docs doesn't treat the backslash to escape things in some situations it previously did.
diff --git a/Doc/library/asyncio-stream.rst b/Doc/library/asyncio-stream.rst
index bee47bc..9b456c1 100644
--- a/Doc/library/asyncio-stream.rst
+++ b/Doc/library/asyncio-stream.rst
@@ -48,7 +48,7 @@
 and work with streams:
 
 
-.. coroutinefunction:: open_connection(host=None, port=None, \*, \
+.. coroutinefunction:: open_connection(host=None, port=None, *, \
                           limit=None, ssl=None, family=0, proto=0, \
                           flags=0, sock=None, local_addr=None, \
                           server_hostname=None, ssl_handshake_timeout=None)
@@ -71,7 +71,7 @@
       The *ssl_handshake_timeout* parameter.
 
 .. coroutinefunction:: start_server(client_connected_cb, host=None, \
-                          port=None, \*, limit=None, \
+                          port=None, *, limit=None, \
                           family=socket.AF_UNSPEC, \
                           flags=socket.AI_PASSIVE, sock=None, \
                           backlog=100, ssl=None, reuse_address=None, \
@@ -103,7 +103,7 @@
 
 .. rubric:: Unix Sockets
 
-.. coroutinefunction:: open_unix_connection(path=None, \*, limit=None, \
+.. coroutinefunction:: open_unix_connection(path=None, *, limit=None, \
                         ssl=None, sock=None, server_hostname=None, \
                         ssl_handshake_timeout=None)
 
@@ -126,7 +126,7 @@
 
 
 .. coroutinefunction:: start_unix_server(client_connected_cb, path=None, \
-                          \*, limit=None, sock=None, backlog=100, ssl=None, \
+                          *, limit=None, sock=None, backlog=100, ssl=None, \
                           ssl_handshake_timeout=None, start_serving=True)
 
    Start a Unix socket server.
@@ -185,7 +185,7 @@
       can be read.  Use the :attr:`IncompleteReadError.partial`
       attribute to get the partially read data.
 
-   .. coroutinemethod:: readuntil(separator=b'\\n')
+   .. coroutinemethod:: readuntil(separator=b'\n')
 
       Read data from the stream until *separator* is found.