Release notes documentation:

• r346331: libomp addition.
• r347110: net.inet.tcp.rexmit_initial sysctl addition.
• r349930: swapon(8) support to trim swap devices.
• r343735: pci_vendors version 2019.02.29.
• r350297: lld enabled as system linker on i386.

While here, move an entry mis-sorted by revision number.

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