bpo-33892: Doc: Use gender neutral words (GH-7770)

(cherry picked from commit 5092439c2cb32112a5869b138011d38491db90a9)

Co-authored-by: Andrés Delfino <adelfino@gmail.com>
diff --git a/Doc/library/ssl.rst b/Doc/library/ssl.rst
index fe50668..2a5b8f6 100644
--- a/Doc/library/ssl.rst
+++ b/Doc/library/ssl.rst
@@ -1395,7 +1395,7 @@
 
 A certificate contains information about two principals.  It contains the name
 of a *subject*, and the subject's public key.  It also contains a statement by a
-second principal, the *issuer*, that the subject is who he claims to be, and
+second principal, the *issuer*, that the subject is who they claim to be, and
 that this is indeed the subject's public key.  The issuer's statement is signed
 with the issuer's private key, which only the issuer knows.  However, anyone can
 verify the issuer's statement by finding the issuer's public key, decrypting the