Fix updating instance docs

src/api/settings.js

@@ -43,7 +43,7 @@ export async function updateInstanceDocument(name, formData, authHost, token) {
 
   return fetch(url, {
     body: formData,
-    method: 'patch',
+    method: 'PATCH',
     headers: authHeaders(token)
   })
     .then((data) => data.json())

src/store/modules/settings.js

@@ -132,7 +132,8 @@ const settings = {
     },
     async UpdateInstanceDocs({ getters }, { name, content }) {
       const formData = new FormData()
-      formData.append('file', content)
+      const blob = new Blob([content], { type: 'text/html' })
+      formData.append('file', blob)
       await updateInstanceDocument(name, formData, getters.authHost, getters.token)
     },
     UpdateSettings({ commit }, { group, key, input, value, type }) {