lambertw: fix jldoctests

Author: alyst

src/lambertw.jl

@@ -9,10 +9,10 @@ domain of the branch `k = 0` is `[-1/e, Inf]`. For `Complex` `z`, and all `k`, t
 the complex plane.
 
 ```jldoctest
-julia> lambertw(-1/e, -1)
+julia> lambertw(-1/ℯ, -1)
 -1.0
 
-julia> lambertw(-1/e, 0)
+julia> lambertw(-1/ℯ, 0)
 -1.0
 
 julia> lambertw(0, 0)
@@ -24,6 +24,10 @@ julia> lambertw(0, -1)
 julia> lambertw(Complex(-10.0, 3.0), 4)
 -0.9274337508660128 + 26.37693445371142im
 ```
+
+```@meta
+DocTestSetup = :(using SpecialFunctions)
+```
 """
 lambertw(z::Number, k::Integer=0; maxiter::Integer=1000) = _lambertw(z, k, maxiter)
 
@@ -269,19 +273,23 @@ If `k=-1` and `imag(z) < 0`, the value on the branch `k=1` is returned.
 
 # Example
 ```jldoctest
-julia> lambertw(-1/e + 1e-18, -1)
+julia> lambertw(-1/ℯ + 1e-18, -1)
 -1.0
 
 julia> lambertwbp(1e-18, -1)
 -2.331643983409312e-9
 
 # Same result, but 1000 times slower
-julia> convert(Float64, (lambertw(-BigFloat(1)/e + BigFloat(10)^(-18), -1) + 1))
+julia> convert(Float64, (lambertw(-BigFloat(1)/ℯ + BigFloat(10)^(-18), -1) + 1))
 -2.331643983409312e-9
 ```
 
+```@meta
+DocTestSetup = :(using SpecialFunctions)
+```
+
 !!! note
-    `lambertwbp` uses a series expansion about the branch point `z=-1/e` to avoid loss of precision.
+    `lambertwbp` uses a series expansion about the branch point `z=-1/ℯ` to avoid loss of precision.
     The loss of precision in `lambertw` is analogous to the loss of precision
     in computing the `sqrt(1-x)` for `x` close to `1`.
 """