Added support for custom content SVG for example

[elbanyaoui]

I added the support for custom content as well, I found line and circles are limited and we needed to add skeleton chart in one of our apps, so I'm suggesting this small update.

Please check if the PR fulfills these requirements

• [ ] The commit messages follow these guidelines
• [ ] Tests for the changes have been added (for bug fixes / features)
• [x] Docs have been added / updated (for bug fixes / features)

What kind of change does this PR introduce? (check one with "x")

• [ ] Bugfix
• [x] Feature
• [ ] Code style update (formatting, local variables)
• [ ] Refactoring (no functional changes, no api changes)
• [ ] Build related changes
• [ ] CI related changes
• [ ] Other. Please describe:

If it is a Bugfix, please describe the root cause and what could have been done to prevent it…

What is the current behavior? (You can link to an open issue here, add screenshots…)

What is the new behavior?

Does this PR introduce a breaking change? (check one with "x")

• [ ] Yes
• [x] No

If this PR contains a breaking change, please describe the impact and migration path for existing applications: …

Other information (if applicable):

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Thanks @willmendesneto

[willmendesneto]

Hi @elbanyaoui sorry for the delay. I'm looking at your pull request right now!

[elbanyaoui]

Hi willmendesneto thanks for your time, I've added all the changes you requested and they're helpful

[elbanyaoui]

@willmendesneto can you re-check, thanks