Update base/strings/basic.jl

Co-authored-by: Matt Bauman <mbauman@gmail.com>

Author: jakobnissen

base/strings/basic.jl

@@ -802,7 +802,7 @@ elsize(s::Type{<:CodeUnits{T}}) where {T} = sizeof(T)
 @propagate_inbounds getindex(s::CodeUnits, i::Int) = codeunit(s.s, i)
 IndexStyle(::Type{<:CodeUnits}) = IndexLinear()
 @inline iterate(s::CodeUnits, i=1) = (i % UInt) - 1 < length(s) ? (@inbounds s[i], i + 1) : nothing
-strides(::CodeUnits) = (1,)
+strides(::CodeUnits{<:Any, <:Union{String, SubString{String}}}) = (1,)
 
 write(io::IO, s::CodeUnits) = write(io, s.s)