doc: Fix doxygen errors

[Empact]

These are all the remaining errors identified via -Werror=documentation, e.g.:

  ./rpc/rawtransaction_util.h:31:13: error: parameter 'prevTxs' not found in the function declaration [-Werror,-Wdocumentation]
    * @param  prevTxs       Array of previous txns outputs that tx depends on but may not yet be in the block chain
              ^~~~~~~
  ./rpc/rawtransaction_util.h:31:13: note: did you mean 'prevTxsUnival'?
    * @param  prevTxs       Array of previous txns outputs that tx depends on but may not yet be in the block chain
              ^~~~~~~
              prevTxsUnival

  netbase.cpp:766:11: error: parameter 'outProxyConnectionFailed[out]' not found in the function declaration [-Werror,-Wdocumentation]
   * @param outProxyConnectionFailed[out] Whether or not the connection to the
            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  netbase.cpp:766:11: note: did you mean 'outProxyConnectionFailed'?
   * @param outProxyConnectionFailed[out] Whether or not the connection to the
            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
            outProxyConnectionFailed

You can use this to run with -Wdocumentation yourself: #14920

[laanwj]

Changes look OK to me, thanks
ACK 297e098