[docs] Change `annotation` to `attribute` #1691

Job	Run time
PHPUnit (7.4, highest, stable, false)	32s
PHPUnit (8.0, highest, stable, false)	27s
PHPUnit (8.1, highest, stable, false)	32s
PHPUnit (8.2, highest, stable, false)	26s
PHPUnit (lowest, stable, 7.4)	32s
PHPUnit (5.4.*, highest, 8.0)	42s
PHPUnit (6.*, highest, 8.3)	31s
PHPUnit (8.3, highest, stable, true)	19s
PHPUnit (8.3, highest, dev, true)	22s
PHPUnit (8.3, highest, dev)	23s
Upload coverage to Codecov	10s
	4m 56s

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