rename duplicate "gnuplot-comment-with-single-quotes" (#83)

to "gnuplot-comment-with-double-quotes"
in order to prevent loading errors

Signed-off-by: Maciej Barć <[email protected]>

Author: Maciej Barć

gnuplot-tests.el

@@ -241,7 +241,7 @@ mutliple # lines #")
 (gnuplot-test-comment gnuplot-comment-with-single-quotes
                       "# a comment 'containing a single-quoted string'")
 
-(gnuplot-test-comment gnuplot-comment-with-single-quotes
+(gnuplot-test-comment gnuplot-comment-with-double-quotes
                       "# a comment \"containing a double-quoted string\"")
 
 (gnuplot-test-comment gnuplot-comment-multiline-with-quotes