Replace the obsolete no-dependencies rationale in every chart helper

The doc comments on the resources and defaultedDict helpers justified the
copy-per-chart with "charts in this repo deliberately have no dependencies".
That rule fell with #214: a dependency is admissible now, just expensive, and
it sits in the README as guideline 14, not 13. The justification still holds,
but its reason is a different one - sharing the helper would mean a library
chart, a second artefact to publish, version and pull for something that
changes about once a year. searxng got that wording in PR #38; this carries it
to the remaining 22 charts, 41 occurrences in all.

Comments only: every touched chart renders byte-identical against its
ci/<chart>/test-values.yaml. Each published chart takes a patch bump,
appVersion and +up suffix untouched; template-chart is never published and
takes none, but is corrected because every new chart inherits from it.

Two repo files carried the same claim at no version cost:
validate-charts.yml explained the all-charts quantity render test with it, and
change-app-version.yml still counted nine images for freesailarr - MediathekArr
made it ten.

rss-bridge/templates/_helpers.tpl

@@ -15,9 +15,10 @@ Rules (variant B, see issue #19):
   - a missing cpu limit is NOT set at all (the kubelet then treats CPU as
     unlimited; CPU is compressible, so this cannot kill the workload).
 
-NOTE: charts in this repo deliberately have no dependencies, so this helper is
-duplicated into every chart's templates/_helpers.tpl with the chart's name as
-define prefix. template-chart holds the reference implementation.
+NOTE: this helper is duplicated into every chart's templates/_helpers.tpl with
+the chart's name as define prefix, because sharing it would mean a library
+chart, and a dependency is admissible but expensive (README, guideline 14) -
+this chart takes none. template-chart holds the reference implementation.
 */}}
 {{- define "rss-bridge.resources" -}}
 {{- $resources := . | default dict -}}