git config doc: fix recent ASCIIDOC formatting regression

Fix a regression in 8c32856 (blame: document --color-* options,
2021-10-08), which added an extra newline before the "+" syntax.

The "Documentation/doc-diff HEAD~ HEAD" output with this applied is:

    [...]
    @@ -1815,13 +1815,13 @@ CONFIGURATION FILE
                specified colors if the line was introduced before the given
                timestamp, overwriting older timestamped colors.

    -       + Instead of an absolute timestamp relative timestamps work as well,
    -       e.g. 2.weeks.ago is valid to address anything older than 2 weeks.
    +           Instead of an absolute timestamp relative timestamps work as well,
    +           e.g.  2.weeks.ago is valid to address anything older than 2 weeks.

    -       + It defaults to blue,12 month ago,white,1 month ago,red, which colors
    -       everything older than one year blue, recent changes between one month
    -       and one year old are kept white, and lines introduced within the last
    -       month are colored red.
    +           It defaults to blue,12 month ago,white,1 month ago,red, which
    +           colors everything older than one year blue, recent changes between
    +           one month and one year old are kept white, and lines introduced
    +           within the last month are colored red.

            color.blame.repeatedLines
                Use the specified color to colorize line annotations for git blame

Signed-off-by: Ævar Arnfjörð Bjarmason <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: avar

Documentation/config/color.txt

@@ -17,11 +17,9 @@ date settings, starting and ending with a color, the dates should be
 set from oldest to newest. The metadata will be colored with the
 specified colors if the line was introduced before the given
 timestamp, overwriting older timestamped colors.
-
 +
 Instead of an absolute timestamp relative timestamps work as well,
 e.g. `2.weeks.ago` is valid to address anything older than 2 weeks.
-
 +
 It defaults to `blue,12 month ago,white,1 month ago,red`, which
 colors everything older than one year blue, recent changes between