feat(discover): extend list of stacking functions (#5074)

- This list is a bit outdated, and there are many more functions that
  discover supports. Updating this to include all of them, but longterm
  probably worth revisiting this section of docs
- This is so the API docs can link here

Author: wmak

src/docs/product/discover-queries/query-builder.mdx

@@ -99,12 +99,28 @@ Above the table, click "Columns" to open the modal that shows you a list of all
 
 You can also add any of the following functions as columns to stack events:
 
+- `any(...)`
+- `apdex(...)`
 - `avg(...)`
-- `count(...)`
+- `count()`
+- `count_if(...)`
+- `count_miserable(...)`
 - `count_unique(...)`
+- `epm()`
+- `eps()`
+- `failure_count()`
+- `failure_rate()`
+- `last_seen()`
 - `max(...)`
 - `min(...)`
+- `percentile(...)`
+- `p50(...)`
+- `p75(...)`
+- `p95(...)`
+- `p99(...)`
+- `p100(...)`
 - `sum(...)`
+- `user_misery(...)`
 
 Each function will ask you to assign a parameter. Some are required while others are optional. Functions will stack events based on the same values. If no functions are applied, the events in your "Query Results" table will remain individually listed. Once you are done editing the columns, click "Apply" and results will be reflected in the query results. Keep in mind, the table may horizontally scroll if many columns are added.