doc: improve wording surrounding TLS 1.3 ciphers

Spelling out numbers makes this part easier to read. Also remove the
unnecessary word 'last'.

PR-URL: #41778
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Mestery <mestery@protonmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Nitzan Uziely <linkgoron@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

doc/api/tls.md

@@ -357,15 +357,15 @@ the default configuration. If these clients _must_ be supported, the
 [TLS recommendations][] may offer a compatible cipher suite. For more details
 on the format, see the OpenSSL [cipher list format][] documentation.
 
-There are only 5 TLSv1.3 cipher suites:
+There are only five TLSv1.3 cipher suites:
 
 * `'TLS_AES_256_GCM_SHA384'`
 * `'TLS_CHACHA20_POLY1305_SHA256'`
 * `'TLS_AES_128_GCM_SHA256'`
 * `'TLS_AES_128_CCM_SHA256'`
 * `'TLS_AES_128_CCM_8_SHA256'`
 
-The first 3 are enabled by default. The last 2 `CCM`-based suites are supported
+The first three are enabled by default. The two `CCM`-based suites are supported
 by TLSv1.3 because they may be more performant on constrained systems, but they
 are not enabled by default since they offer less security.