Update hardware_keyboard_guidelines.md to Fix Typos

[russell-myers1]

Corrected a typo in the phrase "iOS device need lessthan 100" to "iOS devices need less than 100."

Description

This PR corrects a typographical error in the QMK documentation:

Original: "iOS device need lessthan 100."
Corrected: "iOS devices need less than 100."

This was to improve clarity and professionalism of the doc.

Types of Changes

• Core
• Bugfix
• New feature
• Enhancement/optimization
• Keyboard (addition or update)
• Keymap/layout (addition or update)
• Documentation

Issues Fixed or Closed by This PR

• This PR does not address any open issues since the change is minor and does not warrant a separate issue creation. The documentation's direct PR link was used for this fix.

Checklist

• My code follows the code style of this project: C, Python
• [ x] I have read the PR Checklist document and have made the appropriate changes.
• [ x] My change requires a change to the documentation.
• [ x] I have updated the documentation accordingly.
• [x ] I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• [ x] I have tested the changes and verified that they work and don't break anything (as well as I can manage).