Use the broken link highlighter and start to fix those in help.cfg

Thanks to arose to have noticed them when those were invisible.

PS: more to do, and also some translation problem to fix

data/core/help.cfg

@@ -135,7 +135,7 @@ Battle for Wesnoth is a turn-based fantasy strategy game somewhat unusual among
 To begin with, it's best to click the <italic>text=Tutorial</italic> button at the main menu. This will take you to the interactive tutorial, which will teach you the basics of Wesnoth. After this, it is recommended that you play the Heir to the Throne campaign first - click <italic>text=Campaign</italic> then <italic>text='Heir to the Throne'</italic>. As Battle for Wesnoth can be quite challenging, you may wish to start on <italic>text=Easy</italic>." + "
 
 <img>src=help/tooltip.png align=right float=yes</img>" +
-        _"While playing, keep in mind that if you mouse-over many items in the game, such as the information displayed in the status pane, a brief description will be shown explaining each item. This is especially useful when you encounter new <ref>dst=abilities text=abilities</ref> for the first time."
+        _"While playing, keep in mind that if you mouse-over many items in the game, such as the information displayed in the status pane, a brief description will be shown explaining each item. This is especially useful when you encounter new <ref>dst=..abilities_section text=abilities</ref> for the first time."
     [/topic]
 
     [topic]
@@ -157,7 +157,7 @@ When you win a scenario, the map will gray over and the 'End Turn' button will c
     [topic]
         id=recruit_and_recall
         title= _ "Recruiting and Recalling"
-        text="<img>src=help/recruit.png align=left float=yes</img>" + _"Each side begins with one leader in their keep. At the start of any battle, and at times during it, you will need to recruit <ref>dst=units text=units</ref> into your army. To recruit, you must have your leader (for instance, Konrad in the Heir to the Throne campaign) on the Keep square of a <ref>dst=terrain_castle text=Castle</ref>. Then you may recruit by either choosing Recruit from the menu or right-clicking on a hex and selecting <italic>text=Recruit</italic>. This brings up the recruit menu, which lists units available for recruitment, along with their gold cost. Click on a unit to see its statistics, then press the recruit button to recruit it." + _"
+        text="<img>src=help/recruit.png align=left float=yes</img>" + _"Each side begins with one leader in their keep. At the start of any battle, and at times during it, you will need to recruit <ref>dst=..units text=units</ref> into your army. To recruit, you must have your leader (for instance, Konrad in the Heir to the Throne campaign) on the Keep square of a <ref>dst=terrain_castle text=Castle</ref>. Then you may recruit by either choosing Recruit from the menu or right-clicking on a hex and selecting <italic>text=Recruit</italic>. This brings up the recruit menu, which lists units available for recruitment, along with their gold cost. Click on a unit to see its statistics, then press the recruit button to recruit it." + _"
 
 If you right-clicked on a castle hex and selected recruit, the new unit will appear in that square. Otherwise, it will appear in a free square near the keep. You may only recruit as many units as you have free hexes in your castle, and you cannot spend more gold than you actually have on recruiting." + _"
 
@@ -229,7 +229,7 @@ There are two exceptions to this rule: <ref>dst=weaponspecial_magical text='Magi
 
 Each strike which hits causes a base amount of damage depending on the attack type. For instance, an Elvish Fighter with a 5-4 attack does 5 base damage. This is usually modified by two things: <ref>dst=damage_types_and_resistance text=Resistance</ref> and <ref>dst=time_of_day text='Time of Day'</ref>. To see how base damage is modified by the circumstances, select <italic>text='Damage Calculations'</italic> in the attack selection menu." + _"
 
-A few units have special <ref>dst=abilities text=abilities</ref> which affect damage dealt in combat. The most common of these is <ref>dst=weaponspecial_charge text=Charge</ref>, which doubles the damage dealt by both attacker and defender when the unit with Charge attacks."
+A few units have special <ref>dst=..abilities_section text=abilities</ref> which affect damage dealt in combat. The most common of these is <ref>dst=weaponspecial_charge text=Charge</ref>, which doubles the damage dealt by both attacker and defender when the unit with Charge attacks."
     [/topic]
 
     [topic]
@@ -303,7 +303,7 @@ There are two important exceptions to Upkeep: units with the Loyal trait and lea
     [topic]
         id=wrap_up
         title= _ "Wrap Up"
-        text= _ "This concludes the fundamentals of Wesnoth. You might want to read up on Basic Strategy, or familiarise yourself with <ref>dst=traits text=Traits</ref> and <ref>dst=abilities text=Abilities</ref>, but you now know everything you need to know to play the Heir to the Throne campaign. Have fun, and good luck!"
+        text= _ "This concludes the fundamentals of Wesnoth. You might want to read up on Basic Strategy, or familiarise yourself with <ref>dst=..traits_section text=Traits</ref> and <ref>dst=..abilities_section text=Abilities</ref>, but you now know everything you need to know to play the Heir to the Throne campaign. Have fun, and good luck!"
     [/topic]
 
     [topic]