[docs] Fix syntax error in mermaid flowchart for router coprocessor

[shorgi]

Fixes Syntax error in graph for flowchart in https://www.apollographql.com/docs/router/customizations/coprocessor/#how-it-works

Preview: https://deploy-preview-3694--apollo-router-docs.netlify.app/customizations/coprocessor#how-it-works

[github-actions]

@shorgi, please consider creating a changeset entry in /.changesets/. These instructions describe the process and tooling.

[router-perf]

CI performance tests

• step - Basic stress test that steps up the number of users over time
• events_without_dedup - Stress test for events with a lot of users and deduplication DISABLED
• xlarge-request - Stress test with 10 MB request payload
• xxlarge-request - Stress test with 100 MB request payload
• events_big_cap_high_rate - Stress test for events with a lot of users, deduplication enabled and high rate event with a big queue capacity
• const - Basic stress test that runs with a constant number of users
• reload - Reload test over a long period of time at a constant rate of users
• large-request - Stress test with a 1 MB request payload
• events - Stress test for events with a lot of users and deduplication ENABLED
• step-jemalloc-tuning - Clone of the basic stress test for jemalloc tuning
• no-graphos - Basic stress test, no GraphOS.

[Meschreiber]

TY!