Followup to addition of apply

* inline code words easiest as backticks
* prefer https to http
* apply should not be "opinionated" about value vs reference, just transparently pass arguments through

Author: andralex

std/typecons.d

@@ -3441,28 +3441,29 @@ if (is (typeof(nullValue) == T))
     assert(ntts.to!string() == "2.5");
 }
 
+// apply
 /**
 Unpacks the content of a $(D Nullable), performs an operation and packs it again. Does nothing if isNull.
 
-When called on a $(D Nullable), $(D apply) will unpack the value contained in the $(D Nullable),
+When called on a $(D Nullable), `apply` will unpack the value contained in the $(D Nullable),
 pass it to the function you provide and wrap the result in another $(D Nullable) (if necessary).
-If the Nullable is null, $(D apply) will return null itself.
+If the Nullable is null, `apply` will return null itself.
 
 Params:
-    t = a $(D Nullable)
+    t = a `Nullable`
     fun = a function operating on the content of the nullable
 
 Returns:
     `fun(t.get).nullable` if `!t.isNull`, else `Nullable.init`.
 
 See also:
-    $(HTTP en.wikipedia.org/wiki/Monad_(functional_programming)#The_Maybe_monad, The `Maybe` monad)
+    $(HTTPS en.wikipedia.org/wiki/Monad_(functional_programming)#The_Maybe_monad, The `Maybe` monad)
  */
 template apply(alias fun)
 {
     import std.functional : unaryFun;
 
-    auto apply(T)(T t)
+    auto apply(T)(auto ref T t)
     if (isInstanceOf!(Nullable, T) && is(typeof(unaryFun!fun(T.init.get))))
     {
         alias FunType = typeof(unaryFun!fun(T.init.get));