Mistune toc / TableOfContents directive: heading IDs use predictable `toc_N` numbering with no slugification, allowing collision with attacker-controlled `id="toc_N"` content

This update for python-mistune fixes the following issues - CVE-2026-59922: quadratic-time parsing on long runs of some markers in `formatting.py` can lead to DoS (bsc#1271117). - CVE-2026-59923: `HTMLRenderer.safe_url()` does not block percent-encoded javascript URIs and allows for XSS (bsc#1271119). - CVE-2026-59924: improper processing of user-supplied include paths in `Include.parse()` can lead to path traversal and arbitrary file reads (bsc#1271121). - CVE-2026-59925: quadratic-time parsing on long runs of some emphasis pairs in `inline_parser` can lead to DoS (bsc#1271125). - CVE-2026-59926: improper escaping in `render_admonition()` can lead to atribute injection and XSS (bsc#1271127). - CVE-2026-59927: uncontrolled recursion when processing two markdown files that include each other can lead to a DoS (bsc#1271128). - CVE-2026-59928: quadratic-time parsing on long lists of repeated reference-link definitions in `block_parser` can lead to DoS (bsc#1271131). - CVE-2026-59929: HARMFUL_PROTOCOLS list misses legacy and chained schemes and allow arbitrary script execution in user agents (bsc#1271132). - CVE-2026-59930: the `toc` plugin and `TableOfContents` directive generate heading IDs with predictable values and allow for collisions with attacker-controlled `id="toc_N"` content (bsc#1271082).

Where it's fixed