build(deps): Bump docfx from 2.78.1 to 2.78.2

Bumps [docfx](https://github.com/dotnet/docfx) from 2.78.1 to 2.78.2.
- [Release notes](https://github.com/dotnet/docfx/releases)
- [Changelog](https://github.com/dotnet/docfx/blob/main/RELEASENOTE.md)
- [Commits](dotnet/docfx@2.78.1...2.78.2)

---
updated-dependencies:
- dependency-name: docfx
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

.config/dotnet-tools.json

@@ -3,7 +3,7 @@
   "isRoot": true,
   "tools": {
     "docfx": {
-      "version": "2.78.1",
+      "version": "2.78.2",
       "commands": [
         "docfx"
       ]