Apply v-pre to all anchor elements in pageNav

[tlylt]

What is the purpose of this pull request?

• Documentation update
• Bug fix
• Feature addition or enhancement
• Code maintenance
• Others, please explain:

Overview of changes:
Based on the comment: #1724 (comment)
Previously:

• v-pre is added to tag on a need basis, i.e. there are {} in the header text of pageNav headers, and therefore keep to escape from Vue rendering.

Now:

• v-pre is added to all tag for pageNav headers, for simplicity and performance sake.

Functional test files have been updated to deal with the addition of v-pre in HTML and in vue render files:

• 
• 

Anything you'd like to highlight / discuss:
nil

Testing instructions:
nil

Proposed commit message: (wrap lines at 72 characters)
Add v-pre to all anchor elements in pageNav

v-pre is added to anchor elements of pageNav on a need basis
to escape raw {} syntax.

Let's instead add v-pre to all pageNav anchor elements to
keep it simple and performant.

---

Checklist: ☑️

• Updated the documentation for feature additions and enhancements
• Added tests for bug fixes or features
• Linked all related issues
• No unrelated changes

[jonahtanjz]

Thanks for making the change @tlylt :)

I also noticed now that the page nav title has the same issue.

In the frontmatter, if there are curly braces used in the pageNavTitle similar to the headers,

<frontmatter>
  layout: default.md
  pageNav: 2
  pageNavTitle: {% raw %} "Title interpolation {{ test }}" {% endraw %}
</frontmatter>

it will result in the same issue.

Will have to add v-pre to page nav title anchor as well.

[tlylt]

In the frontmatter, if there are curly braces used in the pageNavTitle similar to the headers,

<frontmatter>
  layout: default.md
  pageNav: 2
  pageNavTitle: {% raw %} "Title interpolation {{ test }}" {% endraw %}
</frontmatter>

it will result in the same issue.

Thanks @jonahtanjz! I have addressed the issue and added a test case for it.

[jonahtanjz]

Thanks @tlylt!

LGTM 👍