Fix glitches in changelog

Announce 7.4.18

Announce PHP 7.3.28

GO with 7.4.16

Go with 7.4.15

Announce 7.3.27

Announce 7.3.26

Go with 7.4.14

Fix typo in changelog

Closes GH-384.

Announce 7.3.25

Announce 7.4.13

Announce 7.4.12

Announce 7.3.24

Added missing reference to bug 47021

Announce 7.3.23

Announce 7.4.11

7.2.34 announcement

Announce 7.4.10

Announce 7.3.22

Announce 7.4.9

Announce 7.3.21

7.2.33 announcement

#79657 was cherry-picked in 7.4.7

remove from changelog fix reverted

Announce PHP 7.4.8