capitalise error message

Author: fricklerhandwerk

src/libstore/build/worker.cc

@@ -333,19 +333,19 @@ void Worker::run(const Goals & _topGoals)
                 if (getMachines().empty())
                    throw Error(
                         R"(
-                        unable to start any build;
+                        Unable to start any build;
                         either increase '--max-jobs' or enable remote builds.
 
-                        for more information run 'man nix.conf' and search for '/machines'
+                        For more information run 'man nix.conf' and search for '/machines'.
                         )"
                     );
                 else
                    throw Error(
                         R"(
-                        unable to start any build;
+                        Unable to start any build;
                         remote machines may not have all required system features.
 
-                        for more information run 'man nix.conf' and search for '/machines'
+                        For more information run 'man nix.conf' and search for '/machines'.
                         )"
                     );