[DOC] Use '&&' instead of 'and' in boolean expression

enum.c

@@ -281,12 +281,12 @@ find_i(RB_BLOCK_CALL_FUNC_ARGLIST(i, memop))
  *     (1..100).detect  #=> #<Enumerator: 1..100:detect>
  *     (1..100).find    #=> #<Enumerator: 1..100:find>
  *
- *     (1..10).detect         { |i| i % 5 == 0 and i % 7 == 0 }   #=> nil
- *     (1..10).find           { |i| i % 5 == 0 and i % 7 == 0 }   #=> nil
- *     (1..10).detect(-> {0}) { |i| i % 5 == 0 and i % 7 == 0 }   #=> 0
- *     (1..10).find(-> {0})   { |i| i % 5 == 0 and i % 7 == 0 }   #=> 0
- *     (1..100).detect        { |i| i % 5 == 0 and i % 7 == 0 }   #=> 35
- *     (1..100).find          { |i| i % 5 == 0 and i % 7 == 0 }   #=> 35
+ *     (1..10).detect         { |i| i % 5 == 0 && i % 7 == 0 }   #=> nil
+ *     (1..10).find           { |i| i % 5 == 0 && i % 7 == 0 }   #=> nil
+ *     (1..10).detect(-> {0}) { |i| i % 5 == 0 && i % 7 == 0 }   #=> 0
+ *     (1..10).find(-> {0})   { |i| i % 5 == 0 && i % 7 == 0 }   #=> 0
+ *     (1..100).detect        { |i| i % 5 == 0 && i % 7 == 0 }   #=> 35
+ *     (1..100).find          { |i| i % 5 == 0 && i % 7 == 0 }   #=> 35
  *
  */
 
@@ -350,9 +350,9 @@ find_index_iter_i(RB_BLOCK_CALL_FUNC_ARGLIST(i, memop))
  *
  *  If neither block nor argument is given, an enumerator is returned instead.
  *
- *     (1..10).find_index  { |i| i % 5 == 0 and i % 7 == 0 }  #=> nil
- *     (1..100).find_index { |i| i % 5 == 0 and i % 7 == 0 }  #=> 34
- *     (1..100).find_index(50)                                #=> 49
+ *     (1..10).find_index  { |i| i % 5 == 0 && i % 7 == 0 }  #=> nil
+ *     (1..100).find_index { |i| i % 5 == 0 && i % 7 == 0 }  #=> 34
+ *     (1..100).find_index(50)                               #=> 49
  *
  */