Error loading markdown files (on Windows?)

[nategreen-dh]

I have been using this plugin on Mac, and our CI on linux, for a few weeks with no issues. However, my colleague @jgarayDH recently ran into this error on Windows:

Error loading: C:\sites\dh\design-system\docs\quality-checklist.md
Error loading: C:\sites\dh\design-system\CHANGELOG.md
Error loading: C:\sites\dh\design-system\README.md
Error loading: C:\sites\dh\design-system\dist\README.md
WARN Force closed preview build
ModuleBuildError: Module build failed (from ./node_modules/@storybook-extras/markdown/dist/loader.js):
TypeError: Cannot read properties of null (reading '1')
    at Object.makeTitle (C:\sites\dh\design-system\node_modules\@storybook-extras\devkit\dist\markdown\getMakeTitle.js:34:60)
    at _toMDX (C:\sites\dh\design-system\node_modules\@storybook-extras\devkit\dist\markdown\getMDX.js:39:25)
    at getMDX (C:\sites\dh\design-system\node_modules\@storybook-extras\devkit\dist\markdown\getMDX.js:44:29)
    at Object.<anonymous> (C:\sites\dh\design-system\node_modules\@storybook-extras\devkit\dist\markdown\getLoader.js:33:26)
    at processResult (C:\sites\dh\design-system\node_modules\webpack\lib\NormalModule.js:568:23)
    at C:\sites\dh\design-system\node_modules\webpack\lib\NormalModule.js:646:9
    at C:\sites\dh\design-system\node_modules\loader-runner\lib\LoaderRunner.js:361:14
    at C:\sites\dh\design-system\node_modules\loader-runner\lib\LoaderRunner.js:227:14
    at context.callback (C:\sites\dh\design-system\node_modules\loader-runner\lib\LoaderRunner.js:116:16)
    at Object.<anonymous> (C:\sites\dh\design-system\node_modules\@storybook-extras\devkit\dist\markdown\getLoader.js:39:12)
ModuleBuildError: Module build failed (from ./node_modules/@storybook-extras/markdown/dist/loader.js):
TypeError: Cannot read properties of null (reading '1')
    at Object.makeTitle (C:\sites\dh\design-system\node_modules\@storybook-extras\devkit\dist\markdown\getMakeTitle.js:34:60)
    at _toMDX (C:\sites\dh\design-system\node_modules\@storybook-extras\devkit\dist\markdown\getMDX.js:39:25)
    at getMDX (C:\sites\dh\design-system\node_modules\@storybook-extras\devkit\dist\markdown\getMDX.js:44:29)
    at Object.<anonymous> (C:\sites\dh\design-system\node_modules\@storybook-extras\devkit\dist\markdown\getLoader.js:33:26)
    at processResult (C:\sites\dh\design-system\node_modules\webpack\lib\NormalModule.js:568:23)
    at C:\sites\dh\design-system\node_modules\webpack\lib\NormalModule.js:646:9
    at C:\sites\dh\design-system\node_modules\loader-runner\lib\LoaderRunner.js:361:14
    at C:\sites\dh\design-system\node_modules\loader-runner\lib\LoaderRunner.js:227:14
    at context.callback (C:\sites\dh\design-system\node_modules\loader-runner\lib\LoaderRunner.js:116:16)
    at Object.<anonymous> (C:\sites\dh\design-system\node_modules\@storybook-extras\devkit\dist\markdown\getLoader.js:39:12)
ModuleBuildError: Module build failed (from ./node_modules/@storybook-extras/markdown/dist/loader.js):
TypeError: Cannot read properties of null (reading '1')
    at Object.makeTitle (C:\sites\dh\design-system\node_modules\@storybook-extras\devkit\dist\markdown\getMakeTitle.js:34:60)
    at _toMDX (C:\sites\dh\design-system\node_modules\@storybook-extras\devkit\dist\markdown\getMDX.js:39:25)
    at getMDX (C:\sites\dh\design-system\node_modules\@storybook-extras\devkit\dist\markdown\getMDX.js:44:29)
    at Object.<anonymous> (C:\sites\dh\design-system\node_modules\@storybook-extras\devkit\dist\markdown\getLoader.js:33:26)
    at processResult (C:\sites\dh\design-system\node_modules\webpack\lib\NormalModule.js:568:23)
    at C:\sites\dh\design-system\node_modules\webpack\lib\NormalModule.js:646:9
    at C:\sites\dh\design-system\node_modules\loader-runner\lib\LoaderRunner.js:361:14
    at C:\sites\dh\design-system\node_modules\loader-runner\lib\LoaderRunner.js:227:14
    at context.callback (C:\sites\dh\design-system\node_modules\loader-runner\lib\LoaderRunner.js:116:16)
    at Object.<anonymous> (C:\sites\dh\design-system\node_modules\@storybook-extras\devkit\dist\markdown\getLoader.js:39:12)
ModuleBuildError: Module build failed (from ./node_modules/@storybook-extras/markdown/dist/loader.js):
TypeError: Cannot read properties of null (reading '1')
    at Object.makeTitle (C:\sites\dh\design-system\node_modules\@storybook-extras\devkit\dist\markdown\getMakeTitle.js:34:60)
    at _toMDX (C:\sites\dh\design-system\node_modules\@storybook-extras\devkit\dist\markdown\getMDX.js:39:25)
    at getMDX (C:\sites\dh\design-system\node_modules\@storybook-extras\devkit\dist\markdown\getMDX.js:44:29)
    at Object.<anonymous> (C:\sites\dh\design-system\node_modules\@storybook-extras\devkit\dist\markdown\getLoader.js:33:26)
    at processResult (C:\sites\dh\design-system\node_modules\webpack\lib\NormalModule.js:568:23)
    at C:\sites\dh\design-system\node_modules\webpack\lib\NormalModule.js:646:9
    at C:\sites\dh\design-system\node_modules\loader-runner\lib\LoaderRunner.js:361:14
    at C:\sites\dh\design-system\node_modules\loader-runner\lib\LoaderRunner.js:227:14
    at context.callback (C:\sites\dh\design-system\node_modules\loader-runner\lib\LoaderRunner.js:116:16)
    at Object.<anonymous> (C:\sites\dh\design-system\node_modules\@storybook-extras\devkit\dist\markdown\getLoader.js:39:12)

It looks like maybe it has to do with getMakeTitle, possibly something to do with slashes? (Just a guess, since that's a common issue with Node/shell stuff in Windows.)