docs/cmdline-opts: remove two superfluous "Added in" mentions

The key "added in" phrase for the option itself is added automatically.

Closes #14000

curl: support VLAN Priority: --vlan-priority

Add --vlan-priority option to the command line tool for setting VLAN
priority.

Closes #13907

cmdline-opts: tidy up --ip-tos and --mptcp

To make them render nicer in the manpage and minor polish.

Closes #13906

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