improve error message of setindex! (#1073)

* improve error message of `setindex!`

* Update the error message on src/indexing.jl

Co-authored-by: Yuto Horikawa <[email protected]>

Author: odilf

src/indexing.jl

@@ -1,6 +1,6 @@
 # Default error messages to help users with new types and to avoid subsequent stack overflows
 getindex(a::StaticArray, i::Int) = error("getindex(::$(typeof(a)), ::Int) is not defined.")
-setindex!(a::StaticArray, value, i::Int) = error("setindex!(::$(typeof(a)), value, ::Int) is not defined.")
+setindex!(a::StaticArray, value, i::Int) = error("setindex!(::$(typeof(a)), value, ::Int) is not defined.\n Hint: Use `MArray` or `SizedArray` to create a mutable static array")
 
 #######################################
 ## Multidimensional scalar indexing  ##