Small Typo Fixes for /sites/handbook/source/handbook/engineering/infrastructure/incident-management/index.html.md

Why is this change being made?

I noticed some small mismatched tenses and missing words on lines 407 and 410 of /sites/handbook/source/handbook/engineering/infrastructure/incident-management/index.html.md, this MR fixes that. This helps clarity and ensures grammatical correctness for the document.

Also, there is an incomplete sentence on line 402. I would fix that as well but I am not entirely sure what it's supposed to say, so we should look into fixing that too. Here it is:

Status can be set independent of state. The only time these must align is when an issues is

Author Checklist

• Provided a concise title for this Merge Request (MR)
• Added a description to this MR explaining the reasons for the proposed change, per say why, not just what
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  • If the DRI for the page/s being updated isn’t immediately clear, then assign it to one of the people listed in the Maintained by section on the page being edited
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  • If this is a change that directly impacts the majority of global team members, it should be a candidate for #company-fyi. Please work with internal communications and check the handbook for examples.

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