page-footer: add explanation for three missing exit codes

Added in 7.73.0, 7.77.0 and 7.84.0

Closes #10630

diff --git a/docs/cmdline-opts/page-footer b/docs/cmdline-opts/page-footer
index 38d63ecfbcb0d7a112f61f6ec0d613c114abf906..6e7f9f3916e7e11edcd40699f82d32ad4d356286 100644 (file)
--- a/docs/cmdline-opts/page-footer
+++ b/docs/cmdline-opts/page-footer
@@ -300,6 +300,12 @@ be one out of several problems, see the error message for details.
 .IP 96
 QUIC connection error. This error may be caused by an SSL library error. QUIC
 is the protocol used for HTTP/3 transfers.
+.IP 97
+Proxy handshake error.
+.IP 98
+A client-side certificate is required to complete the TLS handshake.
+.IP 99
+Poll or select returned fatal error.
 .IP XX
 More error codes will appear here in future releases. The existing ones
 are meant to never change.