Development AIs: Add missing translation marks

As found by wmllint

data/ai/dev/akihara_recruitment.cfg

@@ -3,7 +3,7 @@
 
 [ai]
     id=ai_akihara
-    description="Experimental Recruitment AI"
+    description=_"Experimental Recruitment AI"
     version=10800
     [stage]
         id=main_loop
@@ -24,4 +24,4 @@
         {AI_CA_RETREAT}
         {AI_CA_MOVE_TO_TARGETS}
     [/stage]
-[/ai]
+[/ai]

data/ai/dev/formula_ai.cfg

@@ -1,7 +1,7 @@
 #textdomain wesnoth
 [ai]
     id=formula_ai # id is needed to uniquely identify a MP AI, it is not needed in the scenario AI
-    description=Formula AI dev# this description is, again, needed for MP AI (it shows in AI list under this description
+    description=_"Formula AI dev" # this description is, again, needed for MP AI (it shows in AI list under this description
     version=10710 # no spaces here, version should be parsed as int. This version marker is a sign that ALL snippets of AI are written using new syntax
 
     {AI_SIMPLE_FORMULA_AI_EXPERIMENTAL_RECRUITMENT}

data/ai/dev/formula_ai_poisoning.cfg

@@ -2,7 +2,7 @@
 
 [ai]
     id=default_ai_poisoning
-    description= Default AI with poisoning formula
+    description=_"Default AI with poisoning formula"
     version=10703
     [stage]
         engine=cpp

data/ai/dev/idle_ai.cfg

@@ -1,7 +1,7 @@
 #textdomain wesnoth
 [ai]
     id=ai_idle
-    description=Idle AI
+    description=_"Idle AI"
     version=10703
     #well, we can just fall back to idle ai. But we can just do nothing, and it will work (if no additional stages are brought in by other config sources - MP faction config, scenario config, era config, defaults, etc
 [/ai]

data/ai/dev/testing_recruiting.cfg

@@ -2,7 +2,7 @@
 
 [ai]
     id=testing_ai_recruitment
-    description="Experimental Recruitment AI"
+    description=_"Experimental Recruitment AI"
     version=10800
     [stage]
         id=main_loop