merge constructor docs to struct docs

src/Sets/Line2D.jl

@@ -24,37 +24,15 @@ The line ``y = -x + 1``:
 julia> Line2D([1., 1.], 1.)
 Line2D{Float64, Vector{Float64}}([1.0, 1.0], 1.0)
 ```
-"""
-struct Line2D{N,VN<:AbstractVector{N}} <: AbstractPolyhedron{N}
-    a::VN
-    b::N
-
-    # default constructor with length constraint
-    function Line2D(a::VN, b::N) where {N,VN<:AbstractVector{N}}
-        @assert length(a) == 2 "a Line2D must be two-dimensional"
-        @assert !iszero(a) "a line needs a non-zero normal vector"
-        return new{N,VN}(a, b)
-    end
-end
-
-isoperationtype(::Type{<:Line2D}) = false
-
-# constructor from a HalfSpace
-Line2D(c::HalfSpace) = Line2D(c.a, c.b)
-
-"""
-    Line2D(p::AbstractVector, q::AbstractVector)
-
-Constructor of a 2D line from two points.
-
-### Input
 
-- `p` -- point in 2D
-- `q` -- another point in 2D
+The alternative constructor takes two 2D points (`AbstractVector`s) `p` and `q`
+and creates a canonical line from `p` to `q`. See the algorithm section below
+for details.
 
-### Output
-
-The line which passes through `p` and `q`.
+```jldoctest
+julia> Line2D([1., 1.], [2., 2])
+Line2D{Float64, Vector{Float64}}([-1.0, 1.0], 0.0)
+```
 
 ### Algorithm
 
@@ -67,6 +45,18 @@ through these points is
 The particular case ``x₂ = x₁`` defines a line parallel to the ``y``-axis
 (vertical line).
 """
+struct Line2D{N,VN<:AbstractVector{N}} <: AbstractPolyhedron{N}
+    a::VN
+    b::N
+
+    # default constructor with length constraint
+    function Line2D(a::VN, b::N) where {N,VN<:AbstractVector{N}}
+        @assert length(a) == 2 "a Line2D must be two-dimensional"
+        @assert !iszero(a) "a line needs a non-zero normal vector"
+        return new{N,VN}(a, b)
+    end
+end
+
 function Line2D(p::AbstractVector, q::AbstractVector)
     @assert length(p) == length(q) == 2 "a Line2D must be two-dimensional"
 
@@ -78,7 +68,7 @@ function Line2D(p::AbstractVector, q::AbstractVector)
         @assert y₁ != y₂ "a line needs two distinct points"
         a = [one(N), zero(N)]
         b = x₁
-        return LazySets.Line2D(a, b)
+        return Line2D(a, b)
     end
 
     k = (y₁ - y₂) / (x₂ - x₁)
@@ -87,6 +77,11 @@ function Line2D(p::AbstractVector, q::AbstractVector)
     return Line2D(a, b)
 end
 
+isoperationtype(::Type{<:Line2D}) = false
+
+# constructor from a HalfSpace
+Line2D(c::HalfSpace) = Line2D(c.a, c.b)
+
 """
     constraints_list(L::Line2D)