docs: changelog v0.21 fixes (#10037)

Co-authored-by: Jorropo <jorropo.pgm@gmail.com>

docs/changelogs/v0.21.md

@@ -109,7 +109,7 @@ Rationale can be found in [kubo#9913](https://github.com/ipfs/kubo/pull/9913).
 
 The gateway now supports optional CAR export parameters
 `dag-scope=block|entity|all` and `entity-bytes=from:to` as specified in
-[IPIP-402](https://github.com/ipfs/specs/pull/402).
+[IPIP-402](https://specs.ipfs.tech/ipips/ipip-0402/).
 
 Batch block retrieval minimizes round trips, catering to the requirements of
 light HTTP clients for directory enumeration, range requests, and content path
@@ -144,7 +144,7 @@ By trading some upfront DHT caching and increased memory usage,
 one gets provider throughput improvements up to 6 millions times bigger dataset.
 See [the docs](docs/config.md#routingaccelerateddhtclient) for more info.
 
-The `Experimental.AcceleratedDHTClient` flag moved to `[Routing.AcceleratedDHTClient](docs/config.md#routingaccelerateddhtclient)`.
+The `Experimental.AcceleratedDHTClient` flag moved to [`Routing.AcceleratedDHTClient`](/docs/config.md#routingaccelerateddhtclient).
 A config migration has been added to handle this automatically.
 
 A new tracker estimates the providing speed and warns users if they
@@ -228,7 +228,7 @@ should be using AcceleratedDHTClient because they are falling behind.
   - v0.2.1 ([ipfs/go-ipld-legacy#15](https://github.com/ipfs/go-ipld-legacy/pull/15))
   - Expose a constructor for making a decoder with an existing link system ([ipfs/go-ipld-legacy#14](https://github.com/ipfs/go-ipld-legacy/pull/14))
   - Update to v0.2.0 ([ipfs/go-ipld-legacy#13](https://github.com/ipfs/go-ipld-legacy/pull/13))
-  - Remove global variable ([ipfs/go-ipld-legacy#12](https://github.com/ipfs/go-ipld-legacy/pull/12))
+  - Remove global variable ([ipfs/go-ipld-legacy#12](https://github.com/ipfs/go-ipld-legacy/pull/12))
   - sync: update CI config files (#8) ([ipfs/go-ipld-legacy#8](https://github.com/ipfs/go-ipld-legacy/pull/8))
 - github.com/ipfs/go-unixfsnode (v1.6.0 -> v1.7.1):
   - chore: bump to v1.7.1