[Stale Content] Delete M-98-09 FOIA handbook guidance — superseded by FOIA Improvement Act 2016

## What needs to change
The summary file for OMB M-98-09 (Updated Guidance on Developing a Handbook for Individuals Seeking Access of Public Information, 1998) should be removed. This guidance was superseded by the FOIA Improvement Act of 2016 and the related OMB M-19-10, both of which are already listed in the Guidance category.

## Where to find it
Navigate to `pages/_summaries/` and find the file linking to OMB M-98-09. Search if needed:
```
grep -r "M-98-09\|Handbook for Individuals Seeking Access" pages/_summaries/
```

## Before deleting
Confirm nothing else in the repo links to this file:
```
grep -r "m-98-09" pages/
```

## How to verify
Visit https://resources.data.gov/categories/guidance and confirm the M-98-09 entry no longer appears.