private void findNextMatch() {
			try {
				while (it.hasNext()) {
					Symbol sym = getSymbol(it.next());
					if (sym.isExternal()) {
						nextMatch = sym;
						return;
					}
				}
				nextMatch = null;
			}
			catch (IOException e) {
				dbError(e);
				nextMatch = null;
			}
		}
Called by the NamespaceManager when a namespace is removed; remove all symbols that have the
given namespace ID.

@param namespaceID ID of namespace being removed
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/symbol/SymbolManager.java