[llvm] [XCOFF] make related SD symbols as isFunction (PR #69553)

[James Henderson via llvm-commits]

================
@@ -83,8 +83,24 @@ class SymbolizableObjectFile : public SymbolizableModule {
     // getNameFromSymbolTable.
     uint32_t ELFLocalSymIdx;
 
+    // None if this is not a XCOFF local symbol.
----------------
jh7370 wrote:

```suggestion
    // None if this is not an XCOFF local symbol.
```
Nit: I'm assuming the canonical way of saying "XCOFF" is "ex-cough" or similar, so it has a vowel sound to start with and "an" is more appropriate than "a".

https://github.com/llvm/llvm-project/pull/69553