sets: minor documentation fixes [ci skip] (#11377)

Mainly replace a backslash, which was supposed to represent set
difference, with the Unicode symbol for set difference (U+2216).
The backslash did not appear in the output since it is used to
escape characters in reST.

Fix a few typos as well.

1 files changed, 3 insertions, 3 deletions

diff --git a/lib/pure/collections/sets.nim b/lib/pure/collections/sets.nim
index 86a72533e..af3f59a4a 100644
--- a/lib/pure/collections/sets.nim
+++ b/lib/pure/collections/sets.nim
@@ -233,7 +233,7 @@ proc toHashSet*[A](keys: openArray[A]): HashSet[A] =
 iterator items*[A](s: HashSet[A]): A =
   ## Iterates over elements of the set `s`.
   ##
-  ## If you need a sequence with the elelments you can use `sequtils.toSeq
+  ## If you need a sequence with the elements you can use `sequtils.toSeq
   ## template <sequtils.html#toSeq.t,untyped>`_.
   ##
   ## .. code-block::
@@ -439,7 +439,7 @@ proc difference*[A](s1, s2: HashSet[A]): HashSet[A] =
   ##
   ## The same as `s1 - s2 <#-,HashSet[A],HashSet[A]>`_.
   ##
-  ## The difference of two sets is represented mathematically as *A \ B* and is
+  ## The difference of two sets is represented mathematically as *A ∖ B* and is
   ## the set of all objects that are members of `s1` and not members of `s2`.
   ##
   ## See also:
@@ -559,7 +559,7 @@ proc `==`*[A](s, t: HashSet[A]): bool =
   s.counter == t.counter and s <= t
 
 proc map*[A, B](data: HashSet[A], op: proc (x: A): B {.closure.}): HashSet[B] =
-  ## Returns a new set after applying `op` pric on each of the elements of
+  ## Returns a new set after applying `op` proc on each of the elements of
   ##`data` set.
   ##
   ## You can use this proc to transform the elements from a set.