feat(models): add underline to rich text section block element

[zimeg]

Summary

This PR adds underline to the rich text section block element style.

Testing

This snippet might be useful in testing:

fromslack_sdk.models.blocksimport (
RichTextBlock,
RichTextElementParts,
RichTextSectionElement,
)
client.chat_postMessage(
channel=channel_id,
blocks=[
RichTextBlock(
elements=[
RichTextSectionElement(
elements=[
RichTextElementParts.Text(
text="important",
style=RichTextElementParts.TextStyle(
bold=True,
underline=True,
),
),
],
),
],
)
],
)

Category

• slack_sdk.models (UI component builders)

Notes

🏁 This style has not been released to all teams yet! Hoping to have this ready to release when this does go public!

Requirements

• I've read and understood the Contributing Guidelines and have done my best effort to follow them.
• I've read and agree to the Code of Conduct.
• I've run python3 -m venv .venv && source .venv/bin/activate && ./scripts/run_validation.sh after making the changes.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 85.15%. Comparing base (e9e64d8) to head (25e9ec7).
⚠️ Report is 1 commits behind head on main.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@ Coverage Diff @@## main #1771 +/- ##
=======================================
Coverage 85.15% 85.15% =======================================
Files 115 115 Lines 13068 13069 +1 =======================================
+ Hits 11128 11129 +1 
Misses 1940 1940 

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[WilliamBergamin]

Praise 🚀

[mwbrooks]

💅🏻 Yay! Great to see Underline support coming out!

[zimeg]

@WilliamBergamin@mwbrooks I share kind agreement of this excitement so let's merge this now for an upcoming release 👾 ✨