www: broken links for percent-encoded tests

> @laurentsenta i've found this while testing https://github.com/ipfs/gateway-conformance/pull/177:

Opening website's `/tests/test-dag-pb-conversion/get-unix-fs-as-dag-json-with-'accept-application-vnd-ipld-dag-json'-converts-to-the-expected-content-type` produces error:

```
failed to resolve /ipfs/bafybeiawdun4yznzazrp4jxf7wokrhrxp7ruaadunqkhfl7q2yznrctzoi/tests/test-dag-pb-conversion/get-unix-fs-as-dag-json-with-'accept-application-vnd-ipld-dag-json'-converts-to-the-expected-content-type: no link named "get-unix-fs-as-dag-json-with-'accept-application-vnd-ipld-dag-json'-converts-to-the-expected-content-type" under QmTy3DVKxUAUPZB2WASdZoiPc87hcyZVGPWV8Ghwo8ehoA
```

This can be reproduced for every test group that has percent-encoded name:

> example from https://conformance.ipfs.tech/tests/test-dag-pb-conversion/:
>