lint: bump MLC to v0.19.0

Fixes: #31044

This MLC update includes a change which will ignore files being ignored
by git, and help avoid false-positives when linting in this repo.

ci/lint/04_install.sh

@@ -59,7 +59,7 @@ curl -sL "https://github.com/koalaman/shellcheck/releases/download/${SHELLCHECK_
     tar --xz -xf - --directory /tmp/
 mv "/tmp/shellcheck-${SHELLCHECK_VERSION}/shellcheck" /usr/bin/
 
-MLC_VERSION=v0.18.0
+MLC_VERSION=v0.19.0
 MLC_BIN=mlc-x86_64-linux
 curl -sL "https://github.com/becheran/mlc/releases/download/${MLC_VERSION}/${MLC_BIN}" -o "/usr/bin/mlc"
 chmod +x /usr/bin/mlc

test/lint/test_runner/src/main.rs

@@ -516,6 +516,7 @@ fn lint_markdown() -> LintResult {
         "--ignore-path",
         md_ignore_path_str.as_str(),
         "--gitignore",
+        "--gituntracked",
         "--root-dir",
         ".",
     ])