Removed "scheduled for deprecation" pragmas.

The pragmas have not been as effective as we might have liked, since
they only work with templates and can't tell you where in your code you
need to make changes, and they seemed to have been more annoying to
programmers than helpful, so we're going to discontinue them. We'll
leave them in for stuff that's actually been deprecated until deprecated
has been improved enough to take a message, but we'll leave "scheduled
for deprecation" messages to the documentation and changelog.

std/algorithm.d

@@ -3701,6 +3701,9 @@ unittest
 }
 
 /**
+ *  $(RED Scheduled for deprecation. Please use $(XREF algorithm, countUntil)
+ *        instead.)
+ *
  * Same as $(D countUntil). This symbol has been scheduled for
  * deprecation because it is easily confused with the homonym function
  * in $(D std.string).
@@ -3708,8 +3711,6 @@ unittest
 sizediff_t indexOf(alias pred = "a == b", R1, R2)(R1 haystack, R2 needle)
 if (is(typeof(startsWith!pred(haystack, needle))))
 {
-    pragma(msg, "std.algorithm.indexOf has been scheduled for deprecation."
-            " You may want to use std.algorithm.countUntil instead.");
     return countUntil!pred(haystack, needle);
 }