feat(explain): use Distill for explain

[ice1000]

I hereby agree to the terms of the RisingWave Labs, Inc. Contributor License Agreement.

What's changed and what's your intention?

This PR replaces the main usage of Display with Distill.

[ice1000]

Regarding the ─ diffs and spaces, I think there can be a mode in pretty-xmlish to avoid those. Let me think about it.

[ice1000]

I've done a reduction from

to

Very satisfied!!

[codecov]

Codecov Report

Merging #10492 (dd7cffd) into main (5d899ac) will increase coverage by 0.18%.
The diff coverage is 65.95%.

@@            Coverage Diff             @@
##             main   #10492      +/-   ##
==========================================
+ Coverage   70.23%   70.42%   +0.18%     
==========================================
  Files        1269     1269              
  Lines      217030   217016      -14     
==========================================
+ Hits       152432   152833     +401     
+ Misses      64598    64183     -415     

Flag	Coverage Δ
rust	70.42% <65.95%> (+0.18%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
src/frontend/src/handler/create_index.rs	88.06% <0.00%> (ø)
src/frontend/src/handler/create_mv.rs	93.08% <0.00%> (ø)
src/frontend/src/handler/create_sink.rs	94.93% <0.00%> (ø)
src/frontend/src/handler/query.rs	27.24% <0.00%> (ø)
src/frontend/src/optimizer/heuristic_optimizer.rs	89.85% <0.00%> (ø)
.../src/optimizer/plan_visitor/input_ref_validator.rs	81.96% <0.00%> (ø)
src/frontend/src/optimizer/mod.rs	92.17% <55.55%> (ø)
src/frontend/src/optimizer/logical_optimization.rs	96.08% <58.33%> (ø)
src/frontend/planner_test/src/lib.rs	86.83% <100.00%> (ø)
src/frontend/src/handler/explain.rs	69.64% <100.00%> (+0.41%)	⬆️
... and 2 more

... and 66 files with indirect coverage changes

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[stdrc]

Looks very clean to me

[st1page]

LGTM