[llvm] [doc] Add missing info for multiply specifiable objcopy opts (PR #111153)

[via llvm-commits]

================
@@ -120,7 +120,8 @@ multiple file formats.
 .. option:: --remove-symbol-prefix <prefix>
 
  Remove ``<prefix>`` from the start of every symbol name. No-op for symbols that do
- not start with ``<prefix>``.
+ not start with ``<prefix>``. Can be specified multiple times to remove multiple
----------------
bd1976bris wrote:

My point was that "Multiple occurrences are feasible" could be either 1. or 2. 

https://github.com/llvm/llvm-project/pull/111153