Change _zero_algebra -> zero_algebra

The function _zero_algebra was renamed to zero_algebra some
time ago, but not all places calling it were updated.

Author: fingolfin

src/AlgAss/AlgAss.jl

@@ -190,7 +190,7 @@ end
 # Does anyone actually use this?
 function StructureConstantAlgebra(R::Ring, d::Int, arr::Vector{T}) where {T}
   if d == 0
-    return _zero_algebra(R)
+    return zero_algebra(R)
   end
   mult_table = Array{T, 3}(undef, d, d, d)
   n = d^2
@@ -300,7 +300,7 @@ function StructureConstantAlgebra(O::Union{AbsNumFieldOrder, AlgAssAbsOrd}, I::U
   Fp = GF(p, cached = false)
 
   if r == 0
-    A = _zero_algebra(Fp)
+    A = zero_algebra(Fp)
 
     local _image_zero
 
@@ -425,7 +425,7 @@ function StructureConstantAlgebra(I::Union{ AbsNumFieldOrderIdeal, AlgAssAbsOrdI
   Fp = GF(p, cached = false)
 
   if r == 0
-    A = _zero_algebra(Fp)
+    A = zero_algebra(Fp)
 
     local _image_zero
 
@@ -557,7 +557,7 @@ function StructureConstantAlgebra(O::Union{ RelNumFieldOrder{T, S}, AlgAssRelOrd
   r = length(basis_elts)
 
   if r == 0
-    A = _zero_algebra(Fp)
+    A = zero_algebra(Fp)
 
     local _image_zero
 
@@ -712,7 +712,7 @@ function StructureConstantAlgebra(I::Union{ RelNumFieldOrderIdeal{T, S}, AlgAssR
   r = length(basis_elts)
 
   if r == 0
-    A = _zero_algebra(Fp)
+    A = zero_algebra(Fp)
 
     local _image_zero
 
@@ -978,7 +978,7 @@ function subalgebra(A::StructureConstantAlgebra{T}, e::AssociativeAlgebraElem{T,
   r = size(mult_table, 1)
 
   if r == 0
-    eA = _zero_algebra(R)
+    eA = zero_algebra(R)
     return eA, hom(eA, A, zero_matrix(R, 0, n))
   end
 

src/GenOrd/Ideal.jl

@@ -749,7 +749,7 @@ function Hecke.StructureConstantAlgebra(O::GenOrd, I::GenOrdIdl, p::RingElem)
   FQ, phi = residue_field(O.R,p)
 
   if r == 0
-    A = _zero_algebra(FQ)
+    A = zero_algebra(FQ)
 
     local _image_zero