fix airy function deprecations (follow-up to #18050)

[jrevels]

I noticed that the recent airy deprecation warnings added in #18050 were throwing errors due to the (un)layered quoting, so I fixed it. Should I add tests for this, or do we not do tests for depwarns?

This reveals another bug which I'd also be happy to fix, if somebody wants to tell me what to do (I'm not very familiar with these functions, other than needing to support them for automatic differentiation purposes). Calling the two-argument _airy/_airyx methods will call the three-argument _airy/_birymethods, but these latter methods don't seem to be defined anywhere, e.g.:

julia> airy(1, 1)
WARNING: `airy(k::Number,x::Number)` is deprecated, use `airyai(x)`, `airyaiprime(x)`, `airybi(x)` or `airybiprime(x)` instead.
Stacktrace:
 [1] depwarn(::String, ::Symbol) at ./deprecated.jl:64
 [2] airy_depwarn(::Function, ::String, ::String, ::String, ::Bool) at ./deprecated.jl:1289
 [3] airy at ./deprecated.jl:1319 [inlined]
 [4] airy at ./deprecated.jl:1327 [inlined]
 [5] airy(::Int64, ::Int64) at ./deprecated.jl:1326
 [6] eval(::Module, ::Any) at ./boot.jl:236
 [7] eval(::Module, ::Any) at /Users/jarrettrevels/data/repos/julia6/usr/lib/julia/sys.dylib:?
 [8] eval_user_input(::Any, ::Base.REPL.REPLBackend) at ./REPL.jl:66
 [9] macro expansion at ./REPL.jl:97 [inlined]
 [10] (::Base.REPL.##1#2{Base.REPL.REPLBackend})() at ./event.jl:66
while loading no file, in expression starting on line 0
ERROR: MethodError: no method matching _airy(::Complex{Float64}, ::Int32, ::Int32)
Stacktrace:
 [1] _airy(::Int64, ::Complex{Float64}) at ./deprecated.jl:1295
 [2] airy(::Int64, ::Int64) at ./deprecated.jl:1326

[jrevels]

Looks like #19775 beat me by a minute. @simonbyrne Feel free to close this in preference for your PR (though you might want to check out the error I mentioned).