Fix MA0003 Fix All producing invalid named-argument rewrites in multi-argument calls

[Copilot]

MA0003’s code fix could misapply parameter names when multiple arguments in the same invocation were fixed together, producing invalid syntax by stacking name colons onto one argument. This updates Fix All behavior to apply argument naming deterministically per diagnostic span.

• Fix All behavior for MA0003

  • Introduced a dedicated NamedParameterFixAllProvider for NamedParameterFixer.
  • Applies diagnostics in descending source order to avoid span-shift/collision while rewriting arguments in the same call site.
  • Replaces reliance on WellKnownFixAllProviders.BatchFixer for this rule.

• Fixer refactor for span-driven application

  • Reused the same argument-name insertion path from both single-fix and fix-all flows.
  • Switched to span-based argument lookup so each diagnostic maps to the intended ArgumentSyntax after prior edits.

• Regression coverage

  • Added BatchFix_MultipleArgumentsInSingleInvocation to NamedParameterAnalyzerTests.
  • Covers the reported shape where several unnamed null arguments in one invocation must all be named.

// Before batch fix (multiple MA0003 diagnostics on same invocation)
this.InsertStatus(null, null, null, utcStatuses: null, null);

// After
this.InsertStatus(
    reviewStatuses: null,
    courseStatuses: null,
    paymentInfos: null,
    utcStatuses: null,
    dmvStatuses: null);