Fix some outputs in docs (#118)

Author: Tortar

docs/make.jl

@@ -8,6 +8,7 @@ using Documenter
 @info "Building Documentation"
 makedocs(
     sitename = "StreamSampling.jl",
+    modules = [StreamSampling],
     pages = [
         "Introduction" => "index.md",
         "Basics" => "basics.md",

docs/src/perf_tips.md

@@ -26,11 +26,11 @@ iter = 1:10^7;
 Running with both version we get
 
 ```@example 1
-@btime fit_iter!(rs, $iter) setup=(rs = ReservoirSampler{Int}(10, AlgRSWRSKIP(); mutable = true));
+@benchmark fit_iter!(rs, $iter) setup=(rs = ReservoirSampler{Int}(10, AlgRSWRSKIP(); mutable = true))
 ```
 
 ```@example 1
-@btime fit_iter!(rs, $iter) setup=(rs = ReservoirSampler{Int}(10, AlgRSWRSKIP(); mutable = false));
+@benchmark fit_iter!(rs, $iter) setup=(rs = ReservoirSampler{Int}(10, AlgRSWRSKIP(); mutable = false))
 ```
 
 As you can see, the immutable version is 50% faster than