hints docs: explain root hints better

The removed tip seemed especially misleading;
I don't think our root hints could've ever been used that way.
And latency to root servers has practically no impact on latency
of replies to reasonable answers (just like... once per day and TLD).

diff --git a/modules/hints/README.rst b/modules/hints/README.rst
index 97d24ddc6b73ba050a3faeb9b9f6ddcc8b97927b..c2deb5a93bcb822ed2661db690cdfacd703eb0e7 100644 (file)
--- a/modules/hints/README.rst
+++ b/modules/hints/README.rst
@@ -8,8 +8,7 @@ Static hints
 This is a module providing static hints for forward records (A/AAAA) and reverse records (PTR).
 The records can be loaded from ``/etc/hosts``-like files and/or added directly.
 
-You can also use the module to change the root hints; they are used as a safety belt or if the root NS
-drops out of cache.
+You can also use the module to change fallback addresses for the root servers.
 
 .. tip::
 
@@ -110,6 +109,9 @@ Properties
 
   Replace current root hints and return the current table of root hints.
 
+  These root hints are only used as fallback when addresses of ``NS .`` aren't available,
+  e.g. when cache is completely clear.
+
   .. tip:: If no parameters are passed, it only returns current root hints set without changing anything.
 
   Example:
@@ -127,8 +129,6 @@ Properties
       [1] => 202.12.27.33
     }
 
-  .. tip:: A good rule of thumb is to select only a few fastest root hints. The server learns RTT and NS quality over time, and thus tries all servers available. You can help it by preselecting the candidates.
-
 .. function:: hints.use_nodata(toggle)
 
   :param bool toggle: true if enabling NODATA synthesis, false if disabling