Removes `PutPaddedString()` function

This function is unnecessary as it was originally used to support modifiers with `absl::StrFormat()`. This functionality is irrelevant to `absl::StrCat()`.

PiperOrigin-RevId: 484339246
Change-Id: I8c4a0ee01b30aee7a83f6ab54e5465465cc9cc56

absl/strings/internal/stringify_sink.h

@@ -31,8 +31,6 @@ class StringifySink {
 
   void Append(string_view v);
 
-  bool PutPaddedString(string_view v, int width, int precision, bool left);
-
   // Support `absl::Format(&sink, format, args...)`.
   friend void AbslFormatFlush(StringifySink* sink, absl::string_view v) {
     sink->Append(v);

absl/strings/str_cat.cc

@@ -37,30 +37,6 @@ void StringifySink::Append(string_view v) {
   buffer_.append(v.data(), v.size());
 }
 
-bool StringifySink::PutPaddedString(string_view v, int width, int precision,
-                                    bool left) {
-  size_t space_remaining = 0;
-
-  if (width >= 0) space_remaining = static_cast<size_t>(width);
-
-  size_t n = v.size();
-
-  if (precision >= 0) n = (std::min)(n, static_cast<size_t>(precision));
-
-  string_view shown(v.data(), n);
-
-  if (shown.size() < space_remaining) {
-    space_remaining = space_remaining - shown.size();
-  } else {
-    space_remaining = 0;
-  }
-
-  if (!left) Append(space_remaining, ' ');
-  Append(shown);
-  if (left) Append(space_remaining, ' ');
-  return true;
-}
-
 }  // namespace strings_internal
 
 AlphaNum::AlphaNum(Hex hex) {