[2386] Fix API documentation

* Remove exceptions that are not thrown.

src/lib/dns/rdata/generic/detail/ds_like.h

@@ -68,8 +68,6 @@ public:
     /// be valid decimal representations of unsigned 8-bit integers
     /// respectively. The digest field may contain whitespace.
     ///
-    /// \throw MasterLexer::LexerError General parsing error such as
-    /// missing field.
     /// \throw InvalidRdataText if any fields are out of their valid range.
     ///
     /// \param ds_str A string containing the RDATA to be created

src/lib/dns/rdata/generic/nsec_47.cc

@@ -67,8 +67,6 @@ struct NSECImpl {
 /// any invalid mnemonics are found, InvalidRdataText exception is
 /// thrown.
 ///
-/// \throw MasterLexer::LexerError General parsing error such as
-/// missing field.
 /// \throw MissingNameOrigin Thrown when the Next Domain Name is not absolute.
 /// \throw InvalidRdataText if any fields are out of their valid range.
 ///