Use WithCoord parameter parsing for argv

This moves the parameter parsing for the `+<line>:<column>` switch of
the commandline to the `ParametersParser`. The position switch now
respects the `--` separator between switches and files.

src/main.cc

@@ -1102,7 +1102,8 @@ int main(int argc, char* argv[])
                    { "debug", { ArgCompleter{}, "initial debug option value" } },
                    { "version", { {}, "display kakoune version and exit" } },
                    { "ro", { {}, "readonly mode" } },
-                   { "help", { {}, "display a help message and quit" } } }
+                   { "help", { {}, "display a help message and quit" } } },
+        ParameterDesc::Flags::WithCoord
     };
 
     try
@@ -1182,32 +1183,8 @@ int main(int argc, char* argv[])
                               parser.get_switch("i").value_or(StringView{}));
         }
 
-        Vector<StringView> files;
-        Optional<BufferCoord> init_coord;
-        for (auto& name : parser)
-        {
-            if (not name.empty() and name[0_byte] == '+')
-            {
-                if (name == "+" or name  == "+:")
-                {
-                    client_init = client_init + "; exec gj";
-                    continue;
-                }
-                auto colon = find(name, ':');
-                if (auto line = str_to_int_ifp({name.begin()+1, colon}))
-                {
-                    init_coord = std::max<BufferCoord>({0,0}, {
-                        *line - 1,
-                        colon != name.end() ?
-                            str_to_int_ifp({colon+1, name.end()}).value_or(1) - 1
-                          : 0
-                    });
-                    continue;
-                }
-            }
-
-            files.emplace_back(name);
-        }
+        auto init_coord = parser.get_coord();
+        auto files = parser | gather<Vector<StringView>>();
 
         if (auto server_session = parser.get_switch("c"))
         {
@@ -1219,14 +1196,11 @@ int main(int argc, char* argv[])
                     return -1;
                 }
             }
+
             String new_files;
-            for (auto name : files) {
-                new_files += format("edit '{}'", escape(real_path(name), "'", '\''));
-                if (init_coord) {
-                    new_files += format(" {} {}", init_coord->line + 1, init_coord->column + 1);
-                    init_coord.reset();
-                }
-                new_files += ";";
+            for (auto file : files)
+            {
+                new_files += format("edit -- '{}'\n", escape(real_path(file), "'", '\''));
             }
 
             return run_client(*server_session, {}, new_files + client_init, init_coord, ui_type, false);