Documentation of svg oob swaps

[MichaelWest22]

Description

SVGs have issues when you try and modify their contents because they have a different namespace that is only setup when you wrap them in a svg tag. So to allow internal SVG replacment I've found you can use wrapping in both template and svg tags which then works well with OOB swaps. It is also possible to do similar full swaps but you have to use hx-select and its not as easy.

Corresponding issue:

Testing

Performed manual testing of different oob internal svg swaps to check it works as expected

Checklist

• I have read the contribution guidelines
• I have targeted this PR against the correct branch (master for website changes, dev for
  source changes)
• This is either a bugfix, a documentation update, or a new feature that has been explicitly
  approved via an issue
• I ran the test suite locally (npm run test) and verified that it succeeded

[Telroshan]

(Note: took the liberty to fix a typo in the title and added some punctuation.)
Thanks !