Docs: Remove range notation from random score docs
The `random_score` function produces values between 0 (inclusive) and 1
(exclusive) and documented it with fancy methematical range notation. It
is so fancy I thought it was a typo. This changes the documentation to
use words.
Relates to
@@ -208,10 +208,10 @@ not. The number value is of type float.
[[function-random]]
==== Random
-The `random_score` generates scores that are uniformly distributed in [0, 1[.
-By default, it uses the internal Lucene doc ids as a source of randomness,
-which is very efficient but unfortunately not reproducible since documents might
-be renumbered by merges.
+The `random_score` generates scores that are uniformly distributed from 0 up to
+but not including 1. By default, it uses the internal Lucene doc ids as a
+source of randomness, which is very efficient but unfortunately not
+reproducible since documents might be renumbered by merges.
In case you want scores to be reproducible, it is possible to provide a `seed`
and `field`. The final score will then be computed based on this seed, the
