Workflows gotchas: subrequest limit is wrong (per-step vs per-instance, incorrect values)

[FredKSchott]

The workflows gotchas reference at references/workflows/gotchas.md has an incorrect entry in the Limits table:

| Subrequests per step | 50 | 1,000 | Maximum outbound requests per step |

This is wrong in two ways:

1. Per-step vs per-instance — The subrequest limit applies per Workflow instance, not per step. The official docs at https://developers.cloudflare.com/workflows/reference/limits/ state: "Maximum number of subrequests per Workflow instance."

2. Wrong values — The paid plan limit is 10,000 (default), configurable up to 10 million via limits.subrequests in wrangler config. The free plan limit is 50. The table shows 1,000 for paid which is incorrect.

The corrected row should be:

| Subrequests per instance | 50 | 10,000 (default), configurable up to 10M | Maximum outbound requests per workflow instance |

Source: https://developers.cloudflare.com/workflows/reference/limits/