refactor: improve trace and dump format for Call instructions

[zharinov]

Summary

• Change Call instruction successor format from [return] to target : return in both dump and trace
• Remove nav symbols from trace instruction lines (show only in sublines)
• Add definition labels (Name:) in trace after call/return
• Add format_def_name() and format_def_label() helpers in trace.rs
• Update documentation with new format examples

Why

The new target : return format makes it clearer where a Call jumps to and where it returns. Trace now cleanly separates instruction-level info from execution dynamics (nav/match sublines).