Small fix on sec-incident-response.md

Coordinate with internal teams and prepare for the incident investigation:

- Open an incident-focused Slack channel to centralize non-verbal discussion, particularly if the incident is of a sensitive nature. This is done by using `/sirt-escalate` in slack.

- Open an incident-focused Slack channel to centralize non-verbal discussion, particularly if the incident is of a sensitive nature. This is done by using `/sirt_escalate` in slack.

- For artifact handling, a Google Drive folder and shared Google Doc should have been created automatically and linked to the issue.

In the event that an incident needs to be escalated within GitLab, the Security Engineer On Call (SEOC) will page the Security Incident Manager On Call (SIMOC). It is the responsibility of the SIMOC to direct response activities, gather technical resources from required teams, coordinate communication efforts with the Communications Manager On Call, and further escalate the incident as necessary.