docs(nextcloud): Improve method docs of WebDavClient

[provokateurin]

Aligns the documentation of all methods and adds missing docs for parameters (also some slight wording changes).

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 27.21%. Comparing base (4380f5a) to head (a018df2).
Report is 13 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2438   +/-   ##
=======================================
  Coverage   27.21%   27.21%           
=======================================
  Files         370      370           
  Lines      136668   136668           
=======================================
  Hits        37192    37192           
  Misses      99476    99476           

Flag	Coverage Δ		*Carryforward flag
account_repository	99.64% <ø> (ø)
cookie_store	100.00% <ø> (ø)		Carriedforward from 4380f5a
dashboard_app	96.05% <ø> (ø)
dynamite	31.08% <ø> (ø)		Carriedforward from 4380f5a
dynamite_end_to_end_test	61.84% <ø> (ø)		Carriedforward from 4380f5a
dynamite_runtime	85.40% <ø> (ø)		Carriedforward from 4380f5a
neon_dashboard	96.05% <ø> (ø)		Carriedforward from 4380f5a
neon_framework	43.55% <ø> (ø)
neon_http_client	93.28% <ø> (ø)
neon_notifications	100.00% <ø> (ø)		Carriedforward from 4380f5a
neon_talk	99.45% <ø> (ø)		Carriedforward from 4380f5a
nextcloud	23.26% <ø> (ø)
notifications_app	100.00% <ø> (ø)
sort_box	90.90% <ø> (ø)		Carriedforward from 4380f5a
talk_app	99.09% <ø> (ø)

*This pull request uses carry forward flags. Click here to find out more.

Files with missing lines	Coverage Δ
...es/nextcloud/lib/src/api/webdav/webdav_client.dart	99.34% <ø> (ø)