[llvm-objcopy] Fix typo in setSymTab and make setters private.

[alexander-shaposhnikov]

Summary

[NFC] This diff fixes the name of the argument of setSymTab and makes setSymTab/setStrTab private
(to make the public interface a bit cleaner).
(to be honest, I'm not sure if these methods provide any value at all, I would probably remove them, but it's not particularly important)
P.S. I've been working on some other fixes to llvm-objcopy (will create a code review soon), but this tiny change is unrelated that's why I decided to send a separate diff.

[jakehehrlich]

LGTM

Keep the changes coming! I'll be here to review them.

Object.h

struct Symbol {
   uint8_t Visibility;
 
   uint16_t getShndx() const;
 };
 
 class SymbolTableSection : public SectionBase {
   MAKE_SEC_WRITER_FRIEND
 
+  void setStrTab(StringTableSection *StrTab) { SymbolNames = StrTab; }
+
 protected:
   std::vector<std::unique_ptr<Symbol>> Symbols;
   StringTableSection *SymbolNames = nullptr;
 
   using SymPtr = std::unique_ptr<Symbol>;
 
 public:
-  void setStrTab(StringTableSection *StrTab) { SymbolNames = StrTab; }
   void addSymbol(StringRef Name, uint8_t Bind, uint8_t Type,
                  SectionBase *DefinedIn, uint64_t Value, uint8_t Visibility,
                  uint16_t Shndx, uint64_t Sz);
   void addSymbolNames();
   const SectionBase *getStrTab() const { return SymbolNames; }
   const Symbol *getSymbolByIndex(uint32_t Index) const;
   void removeSectionReferences(const SectionBase *Sec) override;
   void localize(std::function<bool(const Symbol &)> ToLocalize);

 };
 
 // Takes the symbol table type to use as a parameter so that we can deduplicate
 // that code between the two symbol table types.
 template <class SymTabType>
 class RelocSectionWithSymtabBase : public RelocationSectionBase {
 private:
   SymTabType *Symbols = nullptr;
+  void setSymTab(SymTabType *SymTab) { Symbols = SymTab; }
 
 protected:
   RelocSectionWithSymtabBase() = default;
 
 public:
-  void setSymTab(SymTabType *StrTab) { Symbols = StrTab; }
   void removeSectionReferences(const SectionBase *Sec) override;
   void initialize(SectionTableRef SecTable) override;
   void finalize() override;
 };
 
 class RelocationSection
     : public RelocSectionWithSymtabBase<SymbolTableSection> {
   MAKE_SEC_WRITER_FRIEND