Documentation: fix mismatched delimiters in git-imap-send

The documentation for git-imap-send uses block delimiters with
mismatched lengths, which Asciidoctor doesn't support.  As a result, the
page is misrendered.  Adjust the delimiters so that they are of the same
length.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-imap-send.txt

@@ -97,7 +97,7 @@ Using direct mode:
     host = imap://imap.example.com
     user = bob
     pass = p4ssw0rd
-..........................
+.........................
 
 Using direct mode with SSL:
 
@@ -109,7 +109,7 @@ Using direct mode with SSL:
     pass = p4ssw0rd
     port = 123
     sslverify = false
-..........................
+.........................
 
 
 EXAMPLE