prefer 'substring'

Inspired by PR #4286

Author: coke

doc/Language/quoting.rakudoc

@@ -382,7 +382,7 @@ them in the resulting words:
 
     say qw{"a b" c}.raku; # OUTPUT: «("\"a", "b\"", "c")␤»
 
-Thus, if you wish to preserve quoted sub-strings as single items in the resulting words
+Thus, if you wish to preserve quoted substrings as single items in the resulting words
 you need to use the C<qww> variant:
 
     say qww{"a b" c}.raku; # OUTPUT: «("a b", "c")␤»
@@ -418,7 +418,7 @@ leaving them in the resulting words:
 
     my $a = 42; say qqw{"$a b" c}.raku;  # OUTPUT: «("\"42", "b\"", "c")␤»
 
-Thus, if you wish to preserve quoted sub-strings as single items in the
+Thus, if you wish to preserve quoted substrings as single items in the
 resulting words you need to use the C<qqww> variant:
 
     my $a = 42; say qqww{"$a b" c}.raku; # OUTPUT: «("42 b", "c")␤»

xt/word-variants.rakutest

@@ -41,6 +41,7 @@ my %variants = %(
     smartmatch => rx:i/ << smart  [\s+|\-] match /,
     subdirectories => rx:i/ << sub \- directories /,
     subdirectory => rx:i/ << sub \- directory /,
+    substring  => rx:i/ << sub \- string /,
     zero-width => rx:i/ << zero \s+ width<!before ' joiner'><!before ' no-break space'> /,
 );