Remove help markup from SPECIAL_NOTES_DEFENSE_CAP

Causes issues with tooltips in-game.

changelog

@@ -151,8 +151,7 @@ Version 1.13.0-dev:
    * Added trait list with links to the help page for unit types
    * Added Defense Cap column to the Terrain Modifiers table in unit help pages
      for units with a defense cap on at least one terrain type, which also now
-     include a note to this effect in their special notes along with a link to
-     an explanation in the Terrains section.
+     include a note to this effect in their special notes.
    * Fixed a bug which caused the terrain section topic not to properly generate
      a list of its contents.
    * Add a new help section to the terrains topic which explains about mixed

data/core/macros/special-notes.cfg

@@ -92,4 +92,4 @@ _" The length of this unit’s weapon allows it to strike first in melee, even i
 _" The victims of this unit’s poison will continually take damage until they can be cured in town or by a unit which cures."#enddef
 
 #define SPECIAL_NOTES_DEFENSE_CAP
-_" This unit has a <ref>text='defense cap' dst='..terrains_section'</ref> on certain terrain types — it cannot achieve a higher defense rating on mixed terrains with such terrain types."#enddef
+_" This unit has a defense cap on certain terrain types — it cannot achieve a higher defense rating on mixed terrains with such terrain types."#enddef

players_changelog

@@ -77,8 +77,7 @@ Version 1.13.0-dev:
    * Several sections have been rewritten or had their layout improved
    * Added Defense Cap column to the Terrain Modifiers table in unit help pages
      for units with a defense cap on at least one terrain type, which also now
-     include a note to this effect in their special notes along with a link to
-     an explanation in the Terrains section.
+     include a note to this effect in their special notes.
    * Autogenerated Time of Day Schedule section
    * Unit types that do not include any visible (hide_help=no) variations no
      longer generate topic sections.