Support multiple commas when escaping lines.

org_mode_samples/lesser_element/lesser_block/example/escaped_lines.org

@@ -1,7 +1,7 @@
 #+begin_example
 ,* foo
-,** bar
-,*** baz
+,,,** bar
+   ,*** baz
     lorem
     , ipsum
 ,#+begin_src dolar

src/parser/lesser_block.rs

@@ -476,8 +476,17 @@ fn content_line<'s>(
     input: OrgSource<'s>,
 ) -> Res<OrgSource<'s>, (Option<OrgSource<'s>>, OrgSource<'s>)> {
     let (remaining, pre_escape_whitespace) = opt(map(
-        tuple((space0, tag(","), peek(alt((tag("#+"), tag("*")))))),
-        |(pre_comma, _, _)| pre_comma,
+        tuple((
+            recognize(tuple((
+                space0,
+                many_till(
+                    tag(","),
+                    peek(tuple((tag(","), alt((tag("#+"), tag("*")))))),
+                ),
+            ))),
+            tag(","),
+        )),
+        |(pre_comma, _)| pre_comma,
     ))(input)?;
     let (remaining, line_post_escape) = recognize(many_till(anychar, line_ending))(remaining)?;
     Ok((remaining, (pre_escape_whitespace, line_post_escape)))