diff --git a/changelog.d/20217.doc b/changelog.d/20217.doc
new file mode 100644
index 0000000000..a7d4590cfa
--- /dev/null
+++ b/changelog.d/20217.doc
@@ -0,0 +1 @@
+Fix small warnings in documentation building tooling output.
\ No newline at end of file
diff --git a/docs/development/synapse_architecture/cancellation.md b/docs/development/synapse_architecture/cancellation.md
index a12f119fb5..91d8c8ca4d 100644
--- a/docs/development/synapse_architecture/cancellation.md
+++ b/docs/development/synapse_architecture/cancellation.md
@@ -284,6 +284,7 @@ await wait_for_room("!aAAaaAaaaAAAaAaAA:matrix.org")
 await wait_for_room("!aAAaaAaaaAAAaAaAA:matrix.org")
 ```
 </td>
+</tr>
 </table>
 
 ### Uncancelled processing
diff --git a/docs/openid.md b/docs/openid.md
index e91d375c41..3115401961 100644
--- a/docs/openid.md
+++ b/docs/openid.md
@@ -140,7 +140,7 @@ The synapse config will look like this:
 3. Add a rule with any name to add the `preferred_username` claim. 
 (See https://auth0.com/docs/customize/rules/create-rules for more information on how to create rules.)
    
-   <details>
+  <details>
     <summary>Code sample</summary>
 
     ```js