REPL: use Base.keyword_syms for sorted_keywords

Author: aviatesk

stdlib/REPL/src/REPLCompletions.jl

@@ -296,6 +296,11 @@ const sorted_keywords = [
     "primitive type", "quote", "return", "struct",
     "try", "using", "while"]
 
+const sorted_keywords = sort!(push!(String.(collect(Base.sorted_keywords)),
+    "abstract type",
+    "mutable struct",
+    "primitive type"))
+
 complete_keyword!(suggestions::Vector{Completion}, s::String) =
     complete_from_list!(suggestions, KeywordCompletion, sorted_keywords, s)