Avoid printing double lines in GitHub Actions

The "terminal" used in github action does not support the use of
carriage return '\r' to move back to column zero and overwrite the
line.  Carriage return will instead move to the next line.
The consequence was that each spec description was printed twice, once
without color before the spec was run and once with color once the
spec had run and the result was known.
Reuse the same mechanism as for specs with descriptions containing
newlines, don't print the spec description before running it unless
color is disabled.

Fixes jorgenschaefer#181.

buttercup.el

@@ -1845,6 +1845,8 @@ EVENT and ARG are described in `buttercup-reporter'."
          (buttercup--print "%s\n" (buttercup--indented-description arg))))
       (`spec-started
        (or buttercup-reporter-batch-quiet-statuses
+           ;; Do not 'pre-print' in github actions unless color is disabled. See #181.
+           (and (not buttercup-color) (getenv "GITHUB_ACTION"))
            (and buttercup-color
                 (string-match-p "[\n\v\f]" (buttercup-spec-description arg)))
            (buttercup--print "%s" (buttercup--indented-description arg))))
@@ -1883,7 +1885,7 @@ EVENT and ARG are described in `buttercup-reporter'."
 (defun buttercup-reporter-batch--print-spec-done-line (spec color)
   "Print the remainder of the SPEC report line for `spec-done'.
 
-If COLOR is non-nil, erace the text so far on the current line
+If COLOR is non-nil, erase the text so far on the current line
 using '\\r' and replace it with the same text colored according to
 the SPEC status. Do not erase and replace if the text would have
 been reprinted with the default color.