Avoid showing the 130 error code after hitting ^C

When a user hits ^C on command line to cancel entering a lengthy
command, $! in __lp_set_prompt is set to 130 (128 + SIGINT). Displaying
this error on the input line (especially in warning colours) makes
little sense.  Therefore, liquidprompt should check if the command
submitted is a real command or is it part of PROMPT_COMMAND in which
case the error does not come from a user's command and should not be
presented.

liquidprompt

@@ -486,6 +486,7 @@ __lp_source_config() {
     LP_ENABLE_OS_VERSION=${LP_ENABLE_OS_VERSION:-1}
     LP_ENABLE_HYPERLINKS=${LP_ENABLE_HYPERLINKS:-0}
     LP_ENABLE_PATH=${LP_ENABLE_PATH:-1}
+    LP_HIDE_EMPTY_ERROR=${LP_HIDE_EMPTY_ERROR:-1}
 
     LP_MARK_DEFAULT="${LP_MARK_DEFAULT:-$_LP_MARK_SYMBOL}"
     LP_MARK_BATTERY="${LP_MARK_BATTERY:-"⌁"}"
@@ -834,6 +835,7 @@ lp_activate() {
         LP_ENABLE_RUNTIME \
         || LP_ENABLE_RUNTIME_BELL \
         || LP_ENABLE_TITLE_COMMAND \
+        || LP_HIDE_EMPTY_ERROR \
     ))
 
     # LP_ENABLE_RUBY_VENV depends either from rvm or rbenv. Thus we cannot
@@ -4810,6 +4812,11 @@ __lp_set_prompt() {
     # As this get the last returned code, it should be called first
     local -i lp_error="$?"
 
+    if (( LP_HIDE_EMPTY_ERROR )); then
+        (( ! ${_LP_REAL_COMMAND:-1} )) && lp_error=0
+        _LP_REAL_COMMAND=0
+    fi
+
     if (( LP_ENABLE_RUNTIME || LP_ENABLE_RUNTIME_BELL )); then
         __lp_runtime_after
     fi
@@ -4858,6 +4865,9 @@ __lp_preexec() {
     if (( LP_ENABLE_TITLE_COMMAND )); then
         __lp_print_title_command
     fi
+    if (( LP_HIDE_EMPTY_ERROR )); then
+        _LP_REAL_COMMAND=1
+    fi
 }
 
 __lp_before_command() {