### Summary
`SBModuleSpecList` already supports `len()` and iteration via `__len__`
and `__iter__`, but is not subscriptable — `specs[0]` raises
`TypeError`.
This adds a `__getitem__` method that supports integer indexing (with
negative index support) and string lookup using `endswith()` matching,
which works for both Unix and Windows paths.
### Supported key types
| Key type | Example | Behavior |
|---|---|---|
| `int` | `specs[0]`, `specs[-1]` | Direct index with negative index
support |
| `str` | `specs['a.out']`, `specs['/usr/lib/liba.dylib']` | Lookup by
basename or partial/full path via `endswith()`. Returns first match or
`None` |
### Error handling
- **`IndexError`** for out-of-bounds integer indices
- **`TypeError`** for unsupported key types (e.g., `float`)
- **`None`** for string lookups with no match
### Before
```python
>>> specs = lldb.SBModuleSpecList.GetModuleSpecifications('/bin/ls')
>>> specs[0]
Traceback (most recent call last):
File "<console>", line 1, in <module>
TypeError: 'SBModuleSpecList' object is not subscriptable
```
### After
```python
>>> import lldb, re
>>> specs = lldb.SBModuleSpecList.GetModuleSpecifications('/bin/ls')
>>> specs[0]
file = '/bin/ls', arch = x86_64-*-linux, uuid = 3CCC0D8A-..., object size = 140928
>>> specs[-1]
file = '/bin/ls', arch = x86_64-*-linux, uuid = 3CCC0D8A-..., object size = 140928
>>> specs['ls']
file = '/bin/ls', arch = x86_64-*-linux, uuid = 3CCC0D8A-..., object size = 140928
>>> specs[999]
IndexError: list index out of range
>>> specs[1.5]
TypeError: unsupported index type: <class 'float'>
```
### Test plan
Added test_module_spec_list_indexing to TestSBModule.py covering:
- Positive and negative integer indexing
- Out-of-bounds raises IndexError
- Unsupported key type raises TypeError
- String lookup by basename and full path (endswith() matching)
- Missing key returns None
```
bin/llvm-lit -sv lldb/test/API/python_api/sbmodule/TestSBModule.py
```
```
PASS: LLDB :: test_GetObjectName_dwarf (TestSBModule.SBModuleAPICase)
PASS: LLDB :: test_GetObjectName_dwo (TestSBModule.SBModuleAPICase)
PASS: LLDB :: test_module_spec_list_indexing_dwarf (TestSBModule.SBModuleAPICase)
PASS: LLDB :: test_module_spec_list_indexing_dwo (TestSBModule.SBModuleAPICase)
----------------------------------------------------------------------
Ran 12 tests in 1.854s
OK (skipped=6)
```
Co-authored-by: Piyush Jaiswal <piyushjais@meta.com>
e8566f83d2