runtime: rename references from Flatten to Decode

[clux]

closes #1517 - we no longer flatten anything.

creates a deprecated type alias for EventFlatten in its place because is actually exposed. Users of WatchStreamExt direct will not notice / care for this, but would be nice if direct users - if they exist - get a warning.

docs updated in kube-rs/website#66

[codecov]

Codecov Report

Attention: Patch coverage is 66.66667% with 2 lines in your changes missing coverage. Please review.

Project coverage is 75.3%. Comparing base (27a2129) to head (5a70ab4).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
kube-runtime/src/utils/watch_ext.rs	50.0%	2 Missing ⚠️

Additional details and impacted files

@@          Coverage Diff          @@
##            main   #1520   +/-   ##
=====================================
  Coverage   75.3%   75.3%           
=====================================
  Files         82      82           
  Lines       7331    7331           
=====================================
  Hits        5515    5515           
  Misses      1816    1816           

Files with missing lines	Coverage Δ
kube-runtime/src/utils/event_decode.rs	91.2% <100.0%> (ø)
kube-runtime/src/utils/mod.rs	62.3% <ø> (ø)
kube-runtime/src/watcher.rs	44.2% <ø> (ø)
kube-runtime/src/utils/watch_ext.rs	22.3% <50.0%> (ø)

[mateiidavid]

No blockers from my side, although I did have some thoughts. Looks good and it's nice we managed to simplify the whole machinery!

[mateiidavid]

nitpicky thought: EventFilter sounds like a good name imo, especially given its use now. I wonder thought if it makes sense to me because I've seen it before. Would users conflate it with PredicateFilter (although, being my own's devil advocate, that's what docs are for).

Would a name like EventDecode work better to convey that what we are actually doing is just taking the inner value?

[clux]

hm, yeah... possibly. maybe i'll hang on to this PR for a little bit first to see if it clashes with use cases for stream forwarding (since it was also running into the same issues.

[clux]

I have updated to EventDecode now.