Fix XML syntax in reference documentation arch/reference.rst

[mg-04]

Description

Fixes several small typos and formatting issues in the FPGA Architecture Reference documentation (doc/src/arch/reference.rst), including:

• Missing/mismatched quotation marks in a few XML example snippets (e.g. priority=10" → priority="10")
• Mismatched opening/closing tags in code examples (e.g. <delay_matrix> closed with </delay>)

No functional/behavioral changes — this is a documentation-only fix.

Related Issue

N/A — this is a small, self-contained documentation fix found while reading the docs; no separate issue was filed beforehand.

Motivation and Context

These typos make some of the example XML snippets invalid, which might confuse readers trying to copy them directly into an architecture file.

How Has This Been Tested?

Visually reviewed the diff against the surrounding correctly-formatted examples in the same file for consistency.

Types of changes

• Bug fix (change which fixes an issue)
• New feature (change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My change requires a change to the documentation
• I have updated the documentation accordingly
• I have added tests to cover my changes
• All new and existing tests passed

[AlexandreSinger]

LGTM, thanks @mg-04 for the fix!

[AmirhosseinPoolad]

Thanks for the changes @mg-04! There was one place where I think the fix wasn't entirely correct, but the other fixes are great.