[docs] Change `annotation` to `attribute` #1721

Job	Run time
PHPUnit (7.4, highest, stable, false)	51s
PHPUnit (8.0, highest, stable, false)	36s
PHPUnit (8.1, highest, stable, false)	48s
PHPUnit (8.2, highest, stable, false)	29s
PHPUnit (lowest, stable, 7.4)	34s
PHPUnit (5.4.*, highest, 8.0)	33s
PHPUnit (6.*, highest, 8.3)	33s
PHPUnit (8.3, highest, stable, true)	19s
PHPUnit (8.3, highest, dev, true)	19s
PHPUnit (8.3, highest, dev)	23s
Upload coverage to Codecov	7s
	5m 32s

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