lib/battery: rename `plugin/battery`

This plugin *only* provides utility functions, so it has zero cost to just being enabled. This allows us to eliminate assumptions from `lib/theme` and several themes.

themes/base.theme.bash

@@ -555,21 +555,15 @@ function prompt_char() {
 }
 
 function battery_char() {
-	# The battery_char function depends on the presence of the battery_percentage function.
-	if [[ "${THEME_BATTERY_PERCENTAGE_CHECK}" == true ]] && _command_exists battery_percentage; then
-		echo -ne "${bold_red?}$(battery_percentage)%"
+	local battery_percentage
+	battery_percentage="$(battery_percentage)"
+	if [[ "${THEME_BATTERY_PERCENTAGE_CHECK}" == true ]]; then
+		echo -e "${bold_red?}${battery_percentage}%"
 	else
 		false
 	fi
 }
 
-if ! _command_exists battery_charge; then
-	# if user has installed battery plugin, skip this...
-	function battery_charge() {
-		: # no op
-	}
-fi
-
 function aws_profile() {
 	if [[ -n "${AWS_DEFAULT_PROFILE:-}" ]]; then
 		echo -ne "${AWS_DEFAULT_PROFILE}"

themes/demula/demula.theme.bash

@@ -82,14 +82,6 @@ ${D_BRANCH_COLOR}%b %r ${D_CHANGES_COLOR}%m%u ${D_DEFAULT_COLOR}"
   fi
 }
 
-# checks if the plugin is installed before calling battery_charge
-safe_battery_charge() {
-  if _command_exists battery_charge ;
-  then
-    battery_charge
-  fi
-}
-
 # -------------------------------------------------------------- PROMPT OUTPUT
 prompt() {
   local LAST_COMMAND_FAILED=$(mitsuhikos_lastcommandfailed)
@@ -101,7 +93,7 @@ prompt() {
   if [[ "$OSTYPE" = 'linux'* ]]
   then
     PS1="${TITLEBAR}${SAVE_CURSOR}${MOVE_CURSOR_RIGHTMOST}${MOVE_CURSOR_5_LEFT}
-$(safe_battery_charge)${RESTORE_CURSOR}\
+$(battery_charge)${RESTORE_CURSOR}\
 ${D_USER_COLOR}\u ${D_INTERMEDIATE_COLOR}\
 at ${D_MACHINE_COLOR}\h ${D_INTERMEDIATE_COLOR}\
 in ${D_DIR_COLOR}\w ${D_INTERMEDIATE_COLOR}\
@@ -117,7 +109,7 @@ in ${D_DIR_COLOR}\w ${D_INTERMEDIATE_COLOR}\
 ${LAST_COMMAND_FAILED}\
 $(demula_vcprompt)\
 $(is_vim_shell)\
-$(safe_battery_charge)
+$(battery_charge)
 ${D_INTERMEDIATE_COLOR}$ ${D_DEFAULT_COLOR}"
   fi
 

themes/rana/rana.theme.bash

@@ -115,14 +115,6 @@ ${D_BRANCH_COLOR}%b %r ${D_CHANGES_COLOR}%m%u ${D_DEFAULT_COLOR}"
   fi
 }
 
-# checks if the plugin is installed before calling battery_charge
-safe_battery_charge() {
-  if _command_exists battery_charge ;
-  then
-    battery_charge
-  fi
-}
-
 prompt_git() {
 	local s='';
 	local branchName='';
@@ -185,7 +177,7 @@ prompt() {
   then
     PS1="${TITLEBAR}
 ${SAVE_CURSOR}${MOVE_CURSOR_RIGHTMOST}${MOVE_CURSOR_5_LEFT}\
-$(safe_battery_charge)${RESTORE_CURSOR}\
+$(battery_charge)${RESTORE_CURSOR}\
 ${D_USER_COLOR}\u ${D_INTERMEDIATE_COLOR}\
 at ${D_MACHINE_COLOR}\h ${D_INTERMEDIATE_COLOR}\
 in ${D_DIR_COLOR}\w ${D_INTERMEDIATE_COLOR}\
@@ -203,7 +195,7 @@ $(prompt_git "$D_INTERMEDIATE_COLOR on $D_GIT_COLOR")\
 ${LAST_COMMAND_FAILED}\
 $(demula_vcprompt)\
 $(is_vim_shell)\
-$(safe_battery_charge)
+$(battery_charge)
 ${D_INTERMEDIATE_COLOR}$ ${D_DEFAULT_COLOR}"
   fi