Fix forced multiline blockquotes in -tgemini.

If a blockquote in -tgemini had hard breaks in it (lines ending
with two spaces), the leading ">" was not printed before this fix.

Thanks to [email protected] for the report, thanks!

gemini.c

@@ -607,7 +607,7 @@ static int
 rndr(struct lowdown_buf *ob, struct lowdown_metaq *mq,
 	struct gemini *st, const struct lowdown_node *n)
 {
-	const struct lowdown_node	*child, *prev;
+	const struct lowdown_node	*child, *prev, *nn;
 	struct link			*l;
 	void				*pp;
 	struct lowdown_buf		*tmpbuf;
@@ -677,13 +677,31 @@ rndr(struct lowdown_buf *ob, struct lowdown_metaq *mq,
 		break;
 	case LOWDOWN_DEFINITION_TITLE:
 	case LOWDOWN_HRULE:
-	case LOWDOWN_LINEBREAK:
 	case LOWDOWN_LISTITEM:
 	case LOWDOWN_META:
 	case LOWDOWN_TABLE_ROW:
 		if (!rndr_buf_vspace(st, ob, 1))
 			return 0;
 		break;
+	case LOWDOWN_LINEBREAK:
+		if (!rndr_buf_vspace(st, ob, 1))
+			return 0;
+
+		/*
+		 * A linebreak is special if invoked within a
+		 * blockquote, because it means we want to output a
+		 * newline but also continue outputting the blockquote
+		 * marker.
+		 */
+
+		for (nn = n->parent; nn != NULL; nn = nn->parent)
+			if (nn->type == LOWDOWN_BLOCKQUOTE) {
+				if (!HBUF_PUTSL(ob, "> "))
+					return 0;
+				st->last_blank = 0;
+				break;
+			}
+		break;
 	case LOWDOWN_IMAGE:
 	case LOWDOWN_LINK:
 	case LOWDOWN_LINK_AUTO:

regress/blockquote-linebreaks.gemini

@@ -0,0 +1,5 @@
+> this is a
+> blockquote
+> with
+> two spaces at the end of
+> ever line

regress/blockquote-linebreaks.html

@@ -0,0 +1,7 @@
+<blockquote>
+<p>this is a<br/>
+blockquote<br/>
+with<br/>
+two spaces at the end of<br/>
+ever line</p>
+</blockquote>

regress/blockquote-linebreaks.md

@@ -0,0 +1,7 @@
+
+> this is a  
+> blockquote  
+> with  
+> two spaces at the end of  
+> ever line
+

regress/blockquote-linebreaks.term

@@ -0,0 +1,5 @@
+      | this is a
+      | blockquote
+      | with
+      | two spaces at the end of
+      | ever line

regress/simple.gemini

@@ -26,20 +26,23 @@ Here’s a numbered list:
 
 Note again how the actual text starts at 4 columns in (4 characters from the left side). Here’s a code sample:
 
-```# Let me re-iterate ...
+```
+# Let me re-iterate ...
 for i in 1 .. 10 { do-something(i) }
 ```
 
 As you probably guessed, indented 4 spaces. By the way, instead of indenting the block, you can use delimited blocks, if you like:
 
-```define foobar() {
+```
+define foobar() {
     print "Welcome to flavor country!";
 }
 ```
 
 (which makes copying & pasting easier). You can optionally mark the delimited block for Pandoc to syntax highlight it:
 
-```import time
+```
+import time
 # Quick, count to ten!
 for i in range(10):
     # (but not *too* quick)
@@ -61,7 +64,8 @@ Now a nested list:
 
 3. Dump everything in the pot and follow this algorithm:
 
-```find wooden spoon
+```
+find wooden spoon
 uncover pot
 stir
 cover pot
@@ -82,7 +86,7 @@ Here’s a link to a website[a], to a local doc[b], and to a section heading in
 
 Tables can look like this:
 
-```
+``` 
 size | material    | color      
 -----|-------------|-------------
 9    | leather     | brown