Documentation/CodingStyle: Fix duplicate "are" typo

The improved paragraph about line lengths contains a sentence with a
duplicate word: there is one "are" at the end of a line, followed by a
second one at the beginning of the next line.

Drop the first one, as that one is part of the longest line.

Fixes: bdc48fa1 ("checkpatch/coding-style: deprecate 80-column warning")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation/process/coding-style.rst

@@ -90,7 +90,7 @@ Statements longer than 80 columns should be broken into sensible chunks,
 unless exceeding 80 columns significantly increases readability and does
 not hide information.
 
-Descendants are always substantially shorter than the parent and are
+Descendants are always substantially shorter than the parent and
 are placed substantially to the right.  A very commonly used style
 is to align descendants to a function open parenthesis.