Dissociation reaction notation
No, no it's not a resonance arrow my friend, it has to be an arrow for equilibrium because it is a reaction equation of $\ce{CH3COOH}$ in its aqueous solution. It will dissociate feebly into its constituent ions because its a really weak acid. Thus establishing equilibrium quite a lot first.

Moreover in a resonance arrow we describe the same compound with different structures (which are all correct) and that is why we establish a resonance hybrid to denote all such possible resonating diagrams in a single diagram fulfilling the properties of the compound.

Nevertheless a resonance arrow can't anyway turn into a dissociation reaction arrow.