typofix: assorted typofixes in comments, documentation and messages

Many instances of duplicate words (e.g. "the the path") and
a few typoes are fixed, originally in multiple patches.

    wildmatch: fix duplicate words of "the"
    t: fix duplicate words of "output"
    transport-helper: fix duplicate words of "read"
    Git.pm: fix duplicate words of "return"
    path: fix duplicate words of "look"
    pack-protocol.txt: fix duplicate words of "the"
    precompose-utf8: fix typo of "sequences"
    split-index: fix typo
    worktree.c: fix typo
    remote-ext: fix typo
    utf8: fix duplicate words of "the"
    git-cvsserver: fix duplicate words

Signed-off-by: Li Peng <lip@dtdream.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/perl/Git.pm b/perl/Git.pm
index 49eb88a..ce7e4e8 100644
--- a/perl/Git.pm
+++ b/perl/Git.pm
@@ -393,7 +393,7 @@
 Execute the given C<COMMAND> in the same way as command_output_pipe()
 does but return both an input pipe filehandle and an output pipe filehandle.
 
-The function will return return C<($pid, $pipe_in, $pipe_out, $ctx)>.
+The function will return C<($pid, $pipe_in, $pipe_out, $ctx)>.
 See C<command_close_bidi_pipe()> for details.
 
 =cut