Migrate StatementPositionRule from SourceKit to SwiftSyntax

Convert StatementPositionRule to use SwiftSyntax instead of SourceKit for
improved performance and more accurate positioning validation.

The SwiftSyntax implementation:
- Uses ViolationsSyntaxVisitor and ViolationsSyntaxRewriter patterns
- Validates else/catch keyword positioning with proper indentation checks
- Supports both default (same line) and uncuddled (next line) modes
- Correctly handles trailing/leading trivia for whitespace validation
- Implements corrections using explicit rewriter for both statement types
- Extracts common validation logic to reduce code duplication
- Skip correcting when there are comments

Author: jpsim

CHANGELOG.md

@@ -35,6 +35,7 @@
   * `file_header`
   * `file_length`
   * `line_length`
+  * `statement_position`
   * `trailing_whitespace`
   * `vertical_whitespace`
   <!-- Keep empty line to have the contributors on a separate line. -->