document the rest of the methods, closes #2739

Author: antoniogamiz

doc/Type/Range.pod6

@@ -379,6 +379,53 @@ C<self.elems>. Returns C<False> otherwise.
     say (6..10).EXISTS-POS(2); # OUTPUT: «True␤»
     say (6..10).EXISTS-POS(7); # OUTPUT: «False␤»
 
+=head2 method AT-POS
+
+Defined as
+
+    multi method AT-POS(Range:D: int \pos)
+    multi method AT-POS(Range:D: int:D \pos)
+
+Checks if the L<Int|/type/Int> position exists and in that case returns the 
+element in that position.
+
+    say (1..4).AT-POS(2) # OUTPUT: «3␤»
+
+=head2 method perl
+
+Defined as
+
+    multi method perl(Range:D:)
+
+Returns an implementation-specific string that produces an L<equivalent|/routine/eqv> object
+when given to L<EVAL|/routine/EVAL>.
+
+    say (1..2).perl # OUTPUT: «1..2␤»
+
+=head2 method fmt
+
+Defined as
+
+    method fmt(|c)
+
+Returns a string where C<min> and C<max> in the L<Range|/type/Range> has been formatted 
+according to C<|c>.
+
+For more information about formats strings, see L<sprintf|/routine/sprintf>.
+
+    say (1..2).fmt("Element: %d", ",") # OUTPUT: «Element: 1,Element: 2␤»
+
+=head2 method WHICH
+
+Defined as
+
+    multi method WHICH (Range:D:)
+
+This returns a string that identifies the object. The string is composed by the
+type of the instance (C<Range>) and the C<min> and C<max> attributes:
+
+    say (1..2).WHICH # OUTPUT: «Range|1..2␤»
+
 =head2 sub infix:<+>
 
     multi sub infix:<+>(Range:D \r, Real:D \v)