Salaams,
The quran has been translated originally by the early missinaries in 1157 and then other english and europeans followed suit.
Obviously they would translate from their own view point - that is the corruption partly.
They believed in magic.
But lets see what is sihr ,what it means from lanes.
(Some examples)
sihr = He was turned from his course,He turned him from hatred to love.
skill,science.
He caused him or enticed him,to incline to him by his soft ,or elegent speech,and by the beuty if its compostion.
He decieved,deluded,or outwitted him.He diverted him,as one diverts a child with food,that he may be contented , and not want milk.
Sahir = Causing the thing to be imagined different from what it really is ;by falsification and deceit.
Miracles are a similer story.
May Allah guid me to the truth.Salaams.