Use .EX/.EE for code examples

A pair of man macros named .EX and .EE are specifically created for
things like code examples. This is ideally suited to typeset markdown
code wrapped into ``` pairs.

Add a simple test case.

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

md2man/roff.go

@@ -37,8 +37,8 @@ const (
 	linkCloseTag     = "\\[ra]"
 	codespanTag      = "\\fB\\fC"
 	codespanCloseTag = "\\fR"
-	codeTag          = "\n.PP\n.RS\n\n.nf\n"
-	codeCloseTag     = "\n.fi\n.RE\n"
+	codeTag          = "\n.EX\n"
+	codeCloseTag     = "\n.EE\n"
 	quoteTag         = "\n.PP\n.RS\n"
 	quoteCloseTag    = "\n.RE\n"
 	listTag          = "\n.RS\n"

md2man/roff_test.go

@@ -10,6 +10,17 @@ type TestParams struct {
 	extensions blackfriday.Extensions
 }
 
+func TestCodeBlocks(t *testing.T) {
+	tests := []string{
+		"```\nsome code\n```\n",
+		".nh\n\n.EX\nsome code\n\n.EE\n",
+
+		"```bash\necho foo\n```\n",
+		".nh\n\n.EX\necho foo\n\n.EE\n",
+	}
+	doTestsParam(t, tests, TestParams{blackfriday.FencedCode})
+}
+
 func TestEmphasis(t *testing.T) {
 	var tests = []string{
 		"nothing inline\n",