Remove source code renderer section from Decks article

[neverett]

Why are the changes needed?

Removes reference to source code renderer from Decks doc since it was removed from flytesnacks example code in flyteorg/flytesnacks#1674

Check all the applicable boxes

• All new and existing tests passed.
• All commits are signed-off.

Related PRs

flyteorg/flytesnacks#1674

Docs link

TK

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 61.06%. Comparing base (1384b32) to head (054622a).
Report is 135 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5397      +/-   ##
==========================================
- Coverage   61.07%   61.06%   -0.02%     
==========================================
  Files         793      793              
  Lines       51210    51210              
==========================================
- Hits        31275    31269       -6     
- Misses      17059    17065       +6     
  Partials     2876     2876              

Flag	Coverage Δ
unittests-datacatalog	69.31% <ø> (ø)
unittests-flyteadmin	58.86% <ø> (-0.05%)	⬇️
unittests-flytecopilot	17.79% <ø> (ø)
unittests-flytectl	67.98% <ø> (ø)
unittests-flyteidl	79.04% <ø> (ø)
unittests-flyteplugins	61.94% <ø> (ø)
unittests-flytepropeller	57.32% <ø> (ø)
unittests-flytestdlib	65.75% <ø> (ø)

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

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.