doc: trailer: remove redundant phrasing

The phrase "many rules" gets essentially repeated again with "many other
rules", so remove this repetition.

Signed-off-by: Linus Arver <linusa@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-interpret-trailers.txt

@@ -72,9 +72,8 @@ inside or after the value. The value may be split over multiple lines
 with each subsequent line starting with at least one whitespace, like
 the "folding" in RFC 822.
 
-Note that 'trailers' do not follow and are not intended to follow many
-rules for RFC 822 headers. For example they do not follow
-the encoding rules and probably many other rules.
+Note that trailers do not follow (nor are they intended to follow) many of the
+rules for RFC 822 headers. For example they do not follow the encoding rule.
 
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