[Misc] Fix 28 SonarCloud issues in various modules

[claude]

Fixes 28 SonarCloud issues in xwiki-commons, all purely mechanical and behaviour-neutral.

Rules fixed

Rule	Count	Change
java:S7476	20	"A single-line comment should start with exactly two slashes" — these were all purely decorative ////// banner lines framing a real comment (or standalone separators). Removed them.
java:S3706	8	collection.stream().forEach(x) → collection.forEach(x).

Notes

• No behaviour change: comment-only edits plus an identical Iterable.forEach call.
• The 30 open java:S3878 issues in xwiki-commons-logging-* were deliberately not touched:
  they are the SLF4J xxx(Marker, String, Object) / xxx(Marker, String, Object, Object) overrides
  that delegate to the varargs overload via new Object[] { ... }. Dropping the array would re-bind
  the call to the fixed-arity overload, i.e. the enclosing method itself — infinite recursion.
• 8 further sites in xwiki-commons-extension-api were left out: that module currently fails its
  own revapi check on master (java.annotation.removed on IndexedExtension#isCompatible,
  fallout from the recent javax→JSpecify @Nullable migration), which is unrelated to this change
  and would have made the PR red.
• Verified with mvn clean install -Plegacy,quality (Checkstyle, Revapi, JaCoCo and the unit tests)
  on the 9 modified modules.

Related

Same sweep in the sibling repos:

• xwiki-platform: [Misc] Fix 48 SonarCloud issues in various modules xwiki-platform#5993
• xwiki-rendering: [Misc] Fix 30 SonarCloud java:S5785 issues by using dedicated JUnit assertions xwiki-rendering#389

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Generated by Claude Code

[vmassol]

@tmortagne I think you're the one using several / characters in code comments such as ////////////////////. They're removed in this PR because they trig somejava:S7476 as indicated in the desc of this PR.

Let me know if instead of removing them you'd want to use something like //--------------- instead. Personally I prefer the removal.

Thx

PS: I'm applying the PR but can still change the code afterwards