restore pathsep() and old sig of print_matrix_vdots for backwards compat (#34314)

Author: JeffBezanson

base/arrayshow.jl

@@ -122,7 +122,7 @@ but it also repeated every M elements if desired.
 """
 function print_matrix_vdots(io::IO, vdots::AbstractString,
                             A::Vector, sep::AbstractString, M::Integer, m::Integer,
-                            pad_right::Bool)
+                            pad_right::Bool = true)
     for k = 1:length(A)
         w = A[k][1] + A[k][2]
         if k % M == m

base/path.jl

@@ -198,6 +198,9 @@ function splitext(path::String)
     a*m.captures[1], String(m.captures[2])
 end
 
+# NOTE: deprecated in 1.4
+pathsep() = path_separator
+
 """
     splitpath(path::AbstractString) -> Vector{String}