TechDraw: Update UI strings for consistency

Closes: #22143

src/Mod/TechDraw/App/DrawViewSymbolPyImp.cpp

@@ -57,7 +57,7 @@ PyObject* DrawViewSymbolPy::dumpSymbol(PyObject *args)
     if (outfile.good()) {
         outfile.close();
     } else {
-        std::string error = std::string("Can't write ");
+        std::string error = std::string("Cannot write");
         error += fileSpec;
         PyErr_SetString(PyExc_RuntimeError, error.c_str());
         return nullptr;