pinnedpubkey.d: fix formatting for version support lists

Closes https://github.com/curl/curl/pull/7340

docs/cmdline-opts/pinnedpubkey.d

@@ -15,12 +15,19 @@ if it does not exactly match the public key provided to this option, curl will
 abort the connection before sending or receiving any data.
 
 PEM/DER support:
-  7.39.0: OpenSSL, GnuTLS and GSKit
-  7.43.0: NSS and wolfSSL
-  7.47.0: mbedtls
+
+7.39.0: OpenSSL, GnuTLS and GSKit
+
+7.43.0: NSS and wolfSSL
+
+7.47.0: mbedtls
+
 sha256 support:
-  7.44.0: OpenSSL, GnuTLS, NSS and wolfSSL
-  7.47.0: mbedtls
+
+7.44.0: OpenSSL, GnuTLS, NSS and wolfSSL
+
+7.47.0: mbedtls
+
 Other SSL backends not supported.
 
 If this option is used several times, the last one will be used.