expose CELL status of a symbol in symtable

Feature or enhancement

Proposal:

symtable symbols have the following predicates, but for some reason no is_cell. Is there a reason for this, or should we expose is_cell as well?

'is_annotated', 'is_assigned', 'is_declared_global', 'is_free', 'is_global', 'is_imported', 'is_local', 'is_namespace', 'is_nonlocal', 'is_parameter', 'is_referenced'

The symbol obviously knows whether it's a cell:

>>> st.get_children()[0].get_symbols()[0]._scope_str
<bound method Symbol._scope_str of <symbol 'x': CELL, USE|DEF_LOCAL>>

Has this already been discussed elsewhere?

No response given

Links to previous discussion of this feature:

No response

Linked PRs

• gh-143549

從 issue 中列出的 symtable Symbol 述詞開始，檢查該 symbol 如何回報其內部的 CELL scope。該 issue 連結了 PR gh-143549，因此先檢視這項工作。完成的標準是，CELL 狀態透過 symtable API 以與現有述詞一致的方式公開。