Spell markdown breaks due to base_url placeholders

[Sturlen]

Spells like Arcane Sight, Snowblind Stare on open5e.com don't render properly because the markdown data is broken. The As you were spell also has an inline link and still loads, however the link does not work.

The reason for this is that the markdown contains two links with {{base_url}} placeholders. Because they each include an underscore, the markdown compiler interprets half of both link as being a <em> element and this breaks the markup. Resulting HTML output:

[true seeing]({{ base<em>url }}/spells/true-seeing) and [detect magic]({{ base</em>url }}/spells/detect-magic)

From deep magic spells.json.

There root problem here is not using a valid URL in the inline links. I think using the full https://open5e.com/api url as a base would be a better solution. For cases where you'd want to rewrite the link you'll still be able to do a search and replace, Not sure if this change is worth changing for v1 or if it should be addressed in v2.

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Additional info:
Base urls were added in #287

Full error log I used to debug the problem:

[Vue warn]: [@vue/server-renderer] Template compilation error: Error parsing JavaScript expression: Unterminated regular expression. (1:7)
1  |  <div><p>The recipient of this spell gains the benefits of both [true seeing]({{ base<em>url }}/spells/true-seeing) and [detect magic]({{ base</em>url }}/spells/detect-magic) until the spell ends, and also knows the name and effect of every spell he or she witnesses during the spell’s duration.</p></div>
   |                                                                                                                                           ^
[nuxt] [request error] [unhandled] [500] Invalid regular expression: missing /
  at Function (<anonymous>)
  at ssrCompile (F:\Projects\open5e\node_modules\@vue\server-renderer\dist\server-renderer.cjs.js:587:35)
  at renderComponentSubTree (F:\Projects\open5e\node_modules\@vue\server-renderer\dist\server-renderer.cjs.js:656:24)
  at renderComponentVNode (F:\Projects\open5e\node_modules\@vue\server-renderer\dist\server-renderer.cjs.js:638:12)
  at renderVNode (F:\Projects\open5e\node_modules\@vue\server-renderer\dist\server-renderer.cjs.js:752:14)
  at renderComponentSubTree (F:\Projects\open5e\node_modules\@vue\server-renderer\dist\server-renderer.cjs.js:707:7)
  at renderComponentVNode (F:\Projects\open5e\node_modules\@vue\server-renderer\dist\server-renderer.cjs.js:638:12)
  at Module.ssrRenderComponent (F:\Projects\open5e\node_modules\@vue\server-renderer\dist\server-renderer.cjs.js:84:10)
  at _sfc_ssrRender (F:\Projects\open5e\components\MdViewer.vue:66:31)
  at renderComponentSubTree (F:\Projects\open5e\node_modules\@vue\server-renderer\dist\server-renderer.cjs.js:692:9)