fix #39982, reduce cursor artifacts in REPL after #39538 (#40411)

Author: JeffBezanson

stdlib/REPL/src/LineEdit.jl

@@ -790,19 +790,23 @@ function edit_insert(s::PromptState, c::StringLike)
         offset = s.ias.curs_row == 1 || s.indent < 0 ?
             sizeof(prompt_string(s.p.prompt)::String) : s.indent
         offset += position(buf) - beginofline(buf) # size of current line
+        spinner = true
         if offset + textwidth(str) <= w
             # Avoid full update when appending characters to the end
             # and an update of curs_row isn't necessary (conservatively estimated)
             write(termbuf, str)
+            spinner = false
         elseif after == 0
             refresh_line(s)
             delayup = false
         else
             delayup = true
         end
         if delayup
-            write(termbuf, spin_seq[mod1(position(buf) - w, length(spin_seq))])
-            cmove_left(termbuf)
+            if spinner
+                write(termbuf, spin_seq[mod1(position(buf) - w, length(spin_seq))])
+                cmove_left(termbuf)
+            end
             s.refresh_wait = Timer(after) do t
                 s.refresh_wait === t || return
                 s.refresh_wait = nothing

stdlib/REPL/src/options.jl

@@ -46,7 +46,7 @@ Options(;
         auto_indent_tmp_off = false,
         auto_indent_bracketed_paste = false,
         auto_indent_time_threshold = 0.005,
-        auto_refresh_time_delay = 0.05,
+        auto_refresh_time_delay = Sys.iswindows() ? 0.05 : 0.0,
         iocontext = Dict{Symbol,Any}()) =
             Options(hascolor, extra_keymap, tabwidth,
                     kill_ring_max, region_animation_duration,