Add an `OpenSSL::X509::Extension#inspect` method

Not being able to inspect the contents of OpenSSL::X509::Extension objects is confusing.

Current Output

cert.extensions
=> 
[#<OpenSSL::X509::Extension:0x00007f8ef961b798>,      
 #<OpenSSL::X509::Extension:0x00007f8ef961b770>,      
 #<OpenSSL::X509::Extension:0x00007f8ef961b748>,      
 #<OpenSSL::X509::Extension:0x00007f8ef961b720>,      
 #<OpenSSL::X509::Extension:0x00007f8ef961b6f8>,      
 #<OpenSSL::X509::Extension:0x00007f8ef961b6d0>,      
 #<OpenSSL::X509::Extension:0x00007f8ef961b6a8>,      
 #<OpenSSL::X509::Extension:0x00007f8ef961b680>,      
 #<OpenSSL::X509::Extension:0x00007f8ef961b658>,      
 #<OpenSSL::X509::Extension:0x00007f8ef961b630>]

Proposed New Output

cert.extensions
# => [#<OpenSSL::X509::Extension: @oid="authorityKeyIdentifier" @value="keyid:B7:6B:A2:EA:A8:AA:84:8C:79:EA:B4:DA:0F:98:B2:C5:95:76:B9:F4\n" @critical=false>,
#<OpenSSL::X509::Extension: @oid="subjectKeyIdentifier" @value="F7:2A:09:D0:24:5B:11:71:EE:BA:BE:F4:3E:1C:3D:56:12:88:16:BB" @critical=false>,
#<OpenSSL::X509::Extension: @oid="subjectAltName" @value="DNS:www.example.org, DNS:example.net, DNS:example.edu, DNS:example.com, DNS:example.org, DNS:www.example.com, DNS:www.example.edu, DNS:www.example.net" @critical=false>,
#<OpenSSL::X509::Extension: @oid="keyUsage" @value="Digital Signature, Key Encipherment" @critical=true>,
#<OpenSSL::X509::Extension: @oid="extendedKeyUsage" @value="TLS Web Server Authentication, TLS Web Client Authentication" @critical=false>,
#<OpenSSL::X509::Extension: @oid="crlDistributionPoints" @value="\nFull Name:\n  URI:http://crl3.digicert.com/DigiCertTLSRSASHA2562020CA1-4.crl\n\nFull Name:\n  URI:http://crl4.digicert.com/DigiCertTLSRSASHA2562020CA1-4.crl\n" @critical=false>,
#<OpenSSL::X509::Extension: @oid="certificatePolicies" @value="Policy: 2.23.140.1.2.2\n  CPS: http://www.digicert.com/CPS\n" @critical=false>,
#<OpenSSL::X509::Extension: @oid="authorityInfoAccess" @value="OCSP - URI:http://ocsp.digicert.com\nCA Issuers - URI:http://cacerts.digicert.com/DigiCertTLSRSASHA2562020CA1-1.crt\n" @critical=false>,
#<OpenSSL::X509::Extension: @oid="basicConstraints" @value="CA:FALSE" @critical=false>,
#<OpenSSL::X509::Extension: @oid="ct_precert_scts" @value="Signed Certificate Timestamp:\n    Version   : v1 (0x0)\n    Log ID    : E8:3E:D0:DA:3E:F5:06:35:32:E7:57:28:BC:89:6B:C9:\n                03:D3:CB:D1:11:6B:EC:EB:69:E1:77:7D:6D:06:BD:6E\n    Timestamp : Mar 14 22:48:46.197 2022 GMT\n    Extensions: none\n    Signature : ecdsa-with-SHA256\n                30:44:02:20:31:78:F3:53:EB:46:7F:BD:32:53:3D:5A:\n                F2:88:6C:D7:AC:BC:42:34:94:2A:B5:E5:0B:92:0B:81:\n                10:C6:C6:FE:02:20:47:74:30:BC:82:C9:21:60:14:7E:\n                F4:9F:25:0F:F3:32:6A:AB:D8:90:DA:9D:61:3C:BB:36:\n                C2:E0:45:9B:73:00\nSigned Certificate Timestamp:\n    Version   : v1 (0x0)\n    Log ID    : 35:CF:19:1B:BF:B1:6C:57:BF:0F:AD:4C:6D:42:CB:BB:\n                B6:27:20:26:51:EA:3F:E1:2A:EF:A8:03:C3:3B:D6:4C\n    Timestamp : Mar 14 22:48:46.204 2022 GMT\n    Extensions: none\n    Signature : ecdsa-with-SHA256\n                30:44:02:20:3B:29:4F:1C:24:50:1A:44:A1:E0:3E:22:\n                89:4D:63:03:8A:97:D6:31:9B:09:3C:D7:AC:9D:D0:ED:\n                88:24:F6:5C:02:20:15:F1:35:A1:A0:E2:E2:8A:A1:8A:\n                9D:8D:36:09:D7:06:5C:EC:C0:CC:2E:ED:4F:A9:BB:3A:\n                D2:C0:92:ED:BE:58\nSigned Certificate Timestamp:\n    Version   : v1 (0x0)\n    Log ID    : B3:73:77:07:E1:84:50:F8:63:86:D6:05:A9:DC:11:09:\n                4A:79:2D:B1:67:0C:0B:87:DC:F0:03:0E:79:36:A5:9A\n    Timestamp : Mar 14 22:48:46.215 2022 GMT\n    Extensions: none\n    Signature : ecdsa-with-SHA256\n                30:45:02:20:29:1E:EA:C0:F2:D0:6F:A5:13:DB:E4:BB:\n                C3:BB:90:B1:BB:03:65:F6:55:5F:F8:3C:16:40:6D:02:\n                5B:5A:4E:90:02:21:00:CB:76:D7:9D:44:D1:8D:86:EC:\n                D8:A4:1E:A0:98:10:72:76:1B:52:42:2E:58:64:BB:29:\n                16:F6:95:1E:97:96:D7" @critical=false>]

Proposed Code

module OpenSSL
  module X509
    class Extension

      def inspect
        "#<#{self.class}: @oid=#{oid.inspect} @value=#{value.inspect} @critical=#{critical?.inspect}>"
      end

    end
  end
end

Start at the OpenSSL::X509::Extension class and inspect the existing oid, value, and critical? methods used by the proposed inspect implementation. Compare the current and proposed outputs in the issue, then verify that inspecting an extension exposes those three values in the shown format.