Adds some missing objectives to xeno tutorial basic (#6448)

# About the pull request

There should've been some `update_objective()` calls at some points in
this, so I've added them.

# Explain why it's good for the game

Whenever you tell a player to do something in a tutorial,
`update_objective()` should be called.

# Changelog
:cl:
qol: Added some missing objectives to the xenomorph - basic tutorial.
/:cl:

Co-authored-by: John Doe <[email protected]>

code/datums/tutorial/xenomorph/xenomorph_basic.dm

@@ -108,6 +108,7 @@
 	UnregisterSignal(human_dummy, COMSIG_MOB_DEATH)
 	message_to_player("Well done. Killing humans is one of many ways to help the hive.")
 	message_to_player("Another way is to <b>capture</b> them. This will grow a new xenomorph inside them which will eventually burst into a new playable xenomorph!")
+	update_objective("")
 	addtimer(CALLBACK(human_dummy, TYPE_PROC_REF(/mob/living, rejuvenate)), 8 SECONDS)
 	addtimer(CALLBACK(src, PROC_REF(proceed_to_tackle_phase)), 10 SECONDS)
 
@@ -139,6 +140,7 @@
 	xeno.melee_damage_lower = 0
 	xeno.melee_damage_upper = 0
 	message_to_player("Well done. Under normal circumstances, you would have to keep tackling the human to keep them down, but for the purposes of this tutorial they will stay down forever.")
+	update_objective("")
 	addtimer(CALLBACK(src, PROC_REF(cap_phase)), 10 SECONDS)
 
 /datum/tutorial/xenomorph/basic/proc/cap_phase()
@@ -147,6 +149,7 @@
 	add_to_tracking_atoms(morpher)
 	add_highlight(morpher, COLOR_YELLOW)
 	message_to_player("In the south west is an egg morpher. Click the egg morpher to take a <b>facehugger</b>.")
+	update_objective("Take a facehugger from the eggmorpher.")
 	RegisterSignal(xeno, COMSIG_XENO_TAKE_HUGGER_FROM_MORPHER, PROC_REF(take_facehugger_phase))
 
 /datum/tutorial/xenomorph/basic/proc/take_facehugger_phase(source, hugger)
@@ -160,6 +163,7 @@
 	add_highlight(hugger, COLOR_YELLOW)
 	message_to_player("This is a facehugger, highlighted in yellow. Pick up the facehugger by clicking it.")
 	message_to_player("Stand next to the downed human and click them to apply the facehugger. Or drop the facehugger near them to see it leap onto their face automatically.")
+	update_objective("Apply the facehugger to the human.")
 	RegisterSignal(hugger, COMSIG_PARENT_QDELETING, PROC_REF(on_hugger_deletion))
 	RegisterSignal(human_dummy, COMSIG_HUMAN_IMPREGNATE, PROC_REF(nest_cap_phase), override = TRUE)
 
@@ -169,6 +173,7 @@
 	morpher.stored_huggers = 1
 	add_highlight(morpher, COLOR_YELLOW)
 	message_to_player("Click the egg morpher to take a <b>facehugger</b>.")
+	update_objective("Take a facehugger from the eggmorpher.")
 	RegisterSignal(xeno, COMSIG_XENO_TAKE_HUGGER_FROM_MORPHER, PROC_REF(take_facehugger_phase))
 
 /datum/tutorial/xenomorph/basic/proc/nest_cap_phase()
@@ -182,6 +187,7 @@
 
 	message_to_player("We should nest the infected human to make sure they don't get away.")
 	message_to_player("Humans cannot escape nests without help, and the nest will keep them alive long enough for our new sister to burst forth.")
+	update_objective("")
 	addtimer(CALLBACK(src, PROC_REF(nest_cap_phase_two)), 10 SECONDS)
 
 /datum/tutorial/xenomorph/basic/proc/nest_cap_phase_two()
@@ -195,13 +201,15 @@
 /datum/tutorial/xenomorph/basic/proc/nest_cap_phase_three()
 	TUTORIAL_ATOM_FROM_TRACKING(/mob/living/carbon/human, human_dummy)
 	message_to_player("Grab the human using your grab intent. Or use control + click.")
+	update_objective("Grab the human using grab intent or ctrl-click.")
 	RegisterSignal(human_dummy, COMSIG_MOVABLE_XENO_START_PULLING, PROC_REF(nest_cap_phase_four))
 
 /datum/tutorial/xenomorph/basic/proc/nest_cap_phase_four()
 	SIGNAL_HANDLER
 	TUTORIAL_ATOM_FROM_TRACKING(/mob/living/carbon/human, human_dummy)
 	UnregisterSignal(human_dummy, COMSIG_MOVABLE_XENO_START_PULLING)
 	message_to_player("Well done. Now devour the human by clicking on your character with the grab selected in your hand. You must not move during this process.")
+	update_objective("Devour the grabbed human by clicking on them with the grab in-hand.")
 	RegisterSignal(human_dummy, COMSIG_MOB_DEVOURED, PROC_REF(nest_cap_phase_five))
 
 /datum/tutorial/xenomorph/basic/proc/nest_cap_phase_five()