chore: bump to vitepress v1.0.0-rc.25

Vitepress moved to an ESM package which leads to vuejs/vitepress#2754 in our case.

One possible solution mentionned by the Vitepress team is to use `mts` files instead of `ts` files, and it seems to work
(`pnpm docs:build` no longer throws).

Author: cexbrayat

docs/.vitepress/config/en.ts renamed to docs/.vitepress/config/en.mts

@@ -1,6 +1,6 @@
-import { enConfig } from './en'
-import { frConfig } from './fr'
-import { sharedConfig } from './shared'
+import { enConfig } from './en.mts'
+import { frConfig } from './fr.mts'
+import { sharedConfig } from './shared.mts'
 import { defineConfig } from 'vitepress'
 
 export default defineConfig({

docs/.vitepress/config/fr.ts renamed to docs/.vitepress/config/fr.mts

@@ -56,7 +56,7 @@
     "typescript": "5.2.2",
     "unplugin-vue-components": "0.25.2",
     "vite": "4.5.0",
-    "vitepress": "1.0.0-beta.7",
+    "vitepress": "1.0.0-rc.25",
     "vitest": "0.34.6",
     "vue": "3.3.7",
     "vue-class-component": "8.0.0-rc.1",