[RAI-35987] Fix name canonicalization backport

[d-netto]

PR Description

Fix a failure introduced in #179.

The function that checks whether an AST node represents a method was incorrect in that PR.

This PR passes the relevant show tests in JuliaLang CI.

julia-RAI % julia                                     
               _
   _       _ _(_)_     |  Documentation: https://docs.julialang.org
  (_)     | (_) (_)    |
   _ _   _| |_  __ _   |  Type "?" for help, "]?" for Pkg help.
  | | | | | | |/ _` |  |
  | | |_| | | | (_| |  |  Version 1.10.2+RAI (2025-03-14)
 _/ |\__'_|_|_|\__'_|  |  dcn-fix-name-canonicalization/614e7b85c2 (fork: 430 commits, 620 days)
|__/                   |

julia> Base.runtests(["show"])
Running parallel tests with:
  nworkers() = 1
  nthreads() = 1
  Sys.CPU_THREADS = 4
  Sys.total_memory() = 64.000 GiB
  Sys.free_memory() = 13.791 GiB

Test  (Worker) | Time (s) | GC (s) | GC % | Alloc (MB) | RSS (MB)
show       (1) |        started at 2025-03-14T11:23:34.328
show       (1) |    11.59 |   0.19 |  1.6 |    2351.93 |   539.17

Test Summary: |   Pass  Broken   Total   Time
  Overall     | 129009       8  129017  12.2s
    SUCCESS

Checklist

Requirements for merging:

• I have opened an issue or PR upstream on JuliaLang/julia: N/A.
• I have removed the port-to-* labels that don't apply.
• I have opened a PR on raicode to test these changes: https://github.com/RelationalAI/raicode/pull/23627.