add some Str examples

Author: szabgab

lib/Str.pod

@@ -131,6 +131,16 @@ Searches for C<$needle> in the string starting from C<$startpos>. It returns
 the offset into the string where C<$needle> was found, and an undefined value
 if it was not found.
 
+Examples:
+
+    say index "Camelia is a butterfly", "a";     # 1
+    say index "Camelia is a butterfly", "a", 2;  #6
+    say index "Camelia is a butterfly", "er";    # 17
+    say index "Camelia is a butterfly", "Camel"; # 0
+    say index "Camelia is a butterfly", "Onion"; # Int()
+
+    say index("Camelia is a butterfly", "Onion") ?? 'OK' !! 'NOT'; # NOT
+
 =head2 rindex
 
     multi sub    rindex(Str:D $haystack, Str:D $needle, Int $startpos = $haystack.chars) returns StrPos
@@ -139,6 +149,11 @@ if it was not found.
 Returns the last position of C<$needle> in C<$haystack> not after C<$startpos>.
 Returns an undefined value if C<$needle> wasn't found.
 
+Examples:
+
+    say rindex "Camelia is a butterfly", "a";     # 11
+    say rindex "Camelia is a butterfly", "a", 10; # 6
+
 =head2 split
 
     multi sub    split(  Str:D $delimiter, Str:D $input, $limit = Inf, :$all) returns Positional
@@ -158,6 +173,17 @@ are included in the result list.
 Note that unlike in Perl 5, empty chunks are not removed from the result list.
 If you want that behavior, consider using C<Str.comb> instead.
 
+Examples:
+
+    say split(';', "a;b;c").perl;          # ("a", "b", "c").list
+    say split(';', "a;b;c", :all).perl;    # ("a", ";", "b", ";", "c").list
+    say split(';', "a;b;c", 2).perl;       # ("a", "b;c").list
+    say split(';', "a;b;c", 2, :all).perl; #("a", ";", "b;c").list
+
+    say split(';', "a;b;c,d").perl;        # ("a", "b", "c,d").list
+    say split(/\;/, "a;b;c,d").perl;       # ("a", "b", "c,d").list
+    say split(/<[;,]>/, "a;b;c,d").perl;   # ("a", "b", "c", "d").list
+
 =head2 comb
 
     multi sub    comb(Str:D   $matcher, Str:D $input, $limit = Inf, Bool :$match)