Add check of MR type label accuracy as code review requirement

What does this MR do and why?

The type label breakdown is used as input for specific calculations used by finance to evaluate the rate of change in the software. Because these have some financial and valuation implications, they have audibility requirements related to SOX audits.

In other words, as a part of being a public company, we need to know where engineering time is being spent, measured by MR labels of feature, bug, maintenance, and others.

This docs-only MR updates the code review and contributor guidelines to ensure that the MR type label (e.g. typefeature , typebug, etc.) is reviewed as accurate prior to merging. Making this review requirement explicit will enable us to rely on this data in cases where we need to demonstrate to external parties (e.g. auditors) that it is accurate.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.