Update src/definitions.jl

Co-authored-by: Seth Axen <seth@sethaxen.com>

Author: vpuri3

src/definitions.jl

@@ -601,7 +601,7 @@ struct AdjointPlan{T,P<:Plan} <: Plan{T}
 end
 
 """
-    p'
+    (p::Plan)'
     adjoint(p::Plan)
 
 Form the adjoint operator of an FFT plan. Returns a plan which performs the adjoint operation