Change Feature request template's label from documentation to enhancement

[ale210]

Overview

We need to change the label applied by the "Feature request" issue template from documentation to enhancement, because every feature suggestion opened through it is currently filed as documentation work. This makes the documentation label useless as a filter and hides real feature requests from anyone browsing by enhancement.

Action Items

• In .github/ISSUE_TEMPLATE/feature_request.md, change the front matter line labels: documentation (line 5 at time of writing) to labels: enhancement. If the line number has drifted, it is the labels: key in the YAML front matter at the top of the file, between title: and assignees:.
• After the PR merges to main, verify: open https://github.com/hackforla/incubator/issues/new/choose, start a "Feature request", and confirm the right-hand Labels box shows enhancement and not documentation. Close the draft without submitting. This step cannot be done from the PR branch — GitHub serves issue templates from the default branch only, so the change is invisible until it merges. Don't close this issue until you have checked.
• Leave the rest of the template alone — only the label is in scope.

Resources/Instructions

• File to edit: https://github.com/hackforla/incubator/blob/main/.github/ISSUE_TEMPLATE/feature_request.md
• Both documentation and enhancement already exist as labels in this repo, so no label needs creating: https://github.com/hackforla/incubator/labels
• This template is one of the ones being kept, not one of the 15 slated for deletion in Delete issue templates that don't apply to incubator #146 — so it is worth fixing rather than removing.