curl: support IP Type of Service / Traffic Class: --ip-tos

Add --ip-tos option to the command line tool for setting TOS for IPv4 or
Traffic Class for IPv6.

Closes #13606

docs/cmdline-opts/Makefile.inc

@@ -136,6 +136,7 @@ DPAGES = \
   include.md \
   insecure.md \
   interface.md \
+  ip-tos.md \
   ipfs-gateway.md \
   ipv4.md \
   ipv6.md \

docs/cmdline-opts/ip-tos.md

@@ -0,0 +1,54 @@
+---
+c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
+SPDX-License-Identifier: curl
+Long: ip-tos
+Arg: <string>
+Help: Set IP Type of Service or Traffic Class
+Added: 8.9.0
+Category: connection
+Protocols: All
+Multi: single
+See-also:
+  - tcp-nodelay
+Example:
+  - --ip-tos CS5 $URL
+---
+
+# `--ip-tos`
+
+Set Type of Service (TOS) for IPv4 or Traffic Class for IPv6. (Added in 8.9.0).
+
+The values allowed for \<string\> can be a numeric value between 1 and 255
+or one of the following:
+
+* CS0
+* CS1
+* CS2
+* CS3
+* CS4
+* CS5
+* CS6
+* CS7
+* AF11
+* AF12
+* AF13
+* AF21
+* AF22
+* AF23
+* AF31
+* AF32
+* AF33
+* AF41
+* AF42
+* AF43
+* EF
+* VOICE-ADMIT
+* ECT1
+* ECT0
+* CE
+* LE
+* LOWCOST
+* LOWDELAY
+* THROUGHPUT
+* RELIABILITY
+* MINCOST

docs/options-in-versions

@@ -98,6 +98,7 @@
 --http3                              7.66.0
 --http3-only                         7.88.0
 --ignore-content-length              7.14.1
+--ip-tos                             8.9.0
 --ipfs-gateway                       8.4.0
 --include (-i)                       4.8
 --insecure (-k)                      7.10