Remove trailing whitespaces.

This really closes #1739 and tip'o'the hat to @coke who usually takes
care of this.

Author: JJ

doc/Language/operators.pod6

@@ -2499,7 +2499,7 @@ lines creating the data structure that is going to be processed
         map( {"VULGAR FRACTION " ~ $^þ }, @fractions); # (1) Adds string to input
 
     # @result is [⅖ ⅗ ⅜ ⅘ ⅚ ⅝ ⅞]
-    
+
 Now we use the feed operator (left-to-right) with parentheses, read top-to-bottom
 
     my @result = (
@@ -2519,7 +2519,7 @@ For illustration, method chaining equivalent, read top-to-bottom, using the same
 Although in this particular case the result is the same, the feed operator C«==>» more clearly
     shows intent with arrow pointing the data flow.  To assign without
     the need of parentheses use another feed operator
-    
+
     my @result;
     <people of earth>
         ==> map({ .tc })
@@ -2529,7 +2529,7 @@ Although in this particular case the result is the same, the feed operator C«==
 
 It can be useful to capture a partial result, however, unlike the
     leftward feed operator, it does require parentheses or a semicolon
-    
+
     my @result;
     <people of earth>
         ==> map({ .tc })