filemerge: avoid putting translated text into docstring

This is follow up of my mistake in e09fad982ef5.

There is no merge tool, which has only one of binary or symlink
capabilities, but this patch lists up all combinations of them for
safety in the future. Maybe, it is too paranoid, though.

mercurial/filemerge.py

@@ -990,9 +990,21 b' def loadinternalmerge(ui, extname, regis'
 
         capabilities = sorted([k for k, v in func.capabilities.items() if v])
         if capabilities:
-            capdesc = _("(actual capabilities: %s)") % ', '.join(capabilities)
+            capdesc = "    (actual capabilities: %s)" % ', '.join(capabilities)
             func.__doc__ = (func.__doc__ +
-                            pycompat.sysstr("\n\n    %s" % capdesc))
+                            pycompat.sysstr("\n\n%s" % capdesc))
+
+    # to put i18n comments into hg.pot for automatically generated texts
+
+    # i18n: "binary" and "symlik" are keywords
+    # i18n: this text is added automatically
+    _("    (actual capabilities: binary, symlink)")
+    # i18n: "binary" is keyword
+    # i18n: this text is added automatically
+    _("    (actual capabilities: binary)")
+    # i18n: "symlink" is keyword
+    # i18n: this text is added automatically
+    _("    (actual capabilities: symlink)")
 
 # load built-in merge tools explicitly to setup internalsdoc
 loadinternalmerge(None, None, internaltool)