theme/pete: adopt automatic history

Use `preexec` and `$HISTCONTROL` to configure _Bash It_'s automatic history management feature.

themes/pete/pete.theme.bash

@@ -7,12 +7,20 @@ function prompt_setter() {
 	scm_char="$(scm_char)"
 	scm_prompt_info="$(scm_prompt_info)"
 	ruby_version_prompt="$(ruby_version_prompt)"
-	_save-and-reload-history 1 # Save history
 	PS1="(${clock_prompt}) ${scm_char} [${blue?}\u${reset_color?}@${green?}\H${reset_color?}] ${yellow?}\w${reset_color?}${scm_prompt_info}${ruby_version_prompt} ${reset_color?} "
 	PS2='> '
 	PS4='+ '
 }
 
+case $HISTCONTROL in
+	*'auto'*)
+		: # Do nothing, already configured.
+		;;
+	*)
+		# Append new history lines to history file
+		HISTCONTROL="${HISTCONTROL:-}${HISTCONTROL:+:}autosave"
+		;;
+esac
 safe_append_prompt_command prompt_setter
 
 SCM_THEME_PROMPT_DIRTY=" ✗"