atomics: tweak [modify|swap]property! docs (JuliaLang#46983)

Author: aviatesk

base/docs/basedocs.jl

@@ -2899,7 +2899,7 @@ Base.setproperty!
     swapproperty!(x, f::Symbol, v, order::Symbol=:not_atomic)
 
 The syntax `@atomic a.b, _ = c, a.b` returns `(c, swapproperty!(a, :b, c, :sequentially_consistent))`,
-where there must be one getfield expression common to both sides.
+where there must be one `getproperty` expression common to both sides.
 
 See also [`swapfield!`](@ref Core.swapfield!)
 and [`setproperty!`](@ref Base.setproperty!).
@@ -2909,9 +2909,9 @@ Base.swapproperty!
 """
     modifyproperty!(x, f::Symbol, op, v, order::Symbol=:not_atomic)
 
-The syntax `@atomic max(a().b, c)` returns `modifyproperty!(a(), :b,
-max, c, :sequentially_consistent))`, where the first argument must be a
-`getfield` expression and is modified atomically.
+The syntax `@atomic op(x.f, v)` (and its equivalent `@atomic x.f op v`) returns
+`modifyproperty!(x, :f, op, v, :sequentially_consistent)`, where the first argument
+must be a `getproperty` expression and is modified atomically.
 
 Invocation of `op(getproperty(x, f), v)` must return a value that can be stored in the field
 `f` of the object `x` by default.  In particular, unlike the default behavior of