docs: fix AEP economics typos

[tharune]

Summary

• fix misspellings in AEP-22's economics proposal text
• clean up the touched trailing whitespace/final newline while editing the file

Verification

• confirmed the old typo patterns were present in src/content/aeps/aep-22/README.md on the current audit stack
• confirmed no existing open PR from this fork targets AEP-22 typo fixes
• ran git diff --check
• ran rg for the corrected typo patterns in AEP-22

[tharune]

Closing this wrong-repo AEP mirror PR per maintainer guidance. Recreated as part of the cleaner AEP-22 source PR here: akash-network/AEP#112