News and compat annotation for JuliaLang#28790

Add a docstring for copyto!(::AbstractMatrix, ::UniformScaling) and
document 1.1 changes.

Author: mortenpi

NEWS.md

@@ -70,6 +70,7 @@ Standard library changes
   * New `sort!(::AbstractArray; dims)` method that can sort the array along the `dims` dimension ([#28902]).
   * `range` now accept `stop` as a positional argument ([#28708]).
   * `parse(Bool, str)` is now supported ([#29997]).
+  * `copyto!(::AbstractMatrix, ::UniformScaling)` supports rectangular matrices now. ([#28790])
 
 Compiler/Runtime improvements
 -----------------------------

stdlib/LinearAlgebra/src/uniformscaling.jl

@@ -212,6 +212,15 @@ function isapprox(J::UniformScaling, A::AbstractMatrix;
 end
 isapprox(A::AbstractMatrix, J::UniformScaling; kwargs...) = isapprox(J, A; kwargs...)
 
+"""
+    copyto!(dest::AbstractMatrix, src::UniformScaling)
+
+Copies a [`UniformScaling`](@ref) onto a matrix.
+
+!!! compat "Julia 1.1"
+    In Julia 1.0 this method only supported a square destination matrix. Julia 1.1. added
+    support for a rectangular matrix.
+"""
 function copyto!(A::AbstractMatrix, J::UniformScaling)
     @assert !has_offset_axes(A)
     fill!(A, 0)