Update to cmark 0.30.2

[apps4everyone]

Update to cmark 0.30.2

[Parth]

@johnxnguyen we've run into a bug which is present on 0.29, but not present on 0.30:

If you try to render a single tick (`) on 0.30.2 with the following C code:

char *content = "`";
int opts = 0;

cmark_node *doc = cmark_parse_document(content, strlen(content), opts);
printf("%d, %d\n", doc->start_column, doc->end_column);
printf("%d, %d\n", doc->first_child->start_column, doc->first_child->end_column);
printf("%d, %d\n", doc->first_child->first_child->start_column, doc->first_child->first_child->end_column);

you get:

1, 1
1, 1
1, 1

as expected, but if you do so with 0.29 (Down's current version which is 3 years old) you get:

1, 1
1, 1
2, 2

which exceeds the document bounds and depending on what you're doing with the AST you'll experience crashes

[Parth]

here is the tree visualized in the xcode debugger:

[Parth]

if you need it here is what the debug visitor sees:

Document
    ↳ Paragraph
        ↳ Text - `

(which is fine)

[Parth]

Here is a small C program you can use for testing:

bugqmark.zip

if you go into the cmark folder and checkout the most recent commit and regen the libs you'll find that the problem goes away and we're returned valid ranges.

[Parth]

Thanks for lending a hand with the C code @steverusso

[Parth]

I updated on my fork, and everything seems to be working fine, will report back as I explore more: https://github.com/Parth/Down