Fix some error message formatting and add some cross-links to docs

Followup to #1747

docs/Plugins.rst

@@ -716,6 +716,8 @@ to always have one or two doors/beds/tables/chairs/etc available, and place
 as many as you like. The plugins then take over and fulfill the orders,
 with minimal space dedicated to stockpiles.
 
+.. _buildingplan-filters:
+
 Item filtering
 --------------
 
@@ -745,6 +747,8 @@ Note that Quickfort mode is only for compatibility with the legacy Python Quickf
 DFHack `quickfort` script does not need Quickfort mode to be enabled. The `quickfort` script
 will successfully integrate with buildingplan as long as the buildingplan plugin is enabled.
 
+.. _buildingplan-settings:
+
 Global settings
 ---------------
 
@@ -755,6 +759,10 @@ can also be set from the ``DFHack#`` prompt once a map is loaded (or from your
 
     buildingplan set <setting> <true|false>
 
+and displayed with::
+
+    buildingplan set
+
 The available settings are:
 
 +----------------+---------+---------------------------------------+

docs/guides/quickfort-user-guide.rst

@@ -1019,21 +1019,22 @@ prevents a building designation from being canceled when a dwarf picks up the
 job but can't find the materials.
 
 As long as the `buildingplan` plugin is enabled, quickfort will use it to manage
-construction. The buildingplan plugin also has an "enabled" setting for each
+construction. The buildingplan plugin has an `"enabled" setting
-building type, but that setting only applies to the buildingplan user interface.
+<buildingplan-settings>` for each building type, but those settings only apply
-In addition, buildingplan has a "quickfort_mode" setting for compatibility with
+to buildings created through the buildingplan user interface. In addition,
-legacy Python Quickfort. This setting has no effect on DFHack Quickfort, which
+buildingplan has a "quickfort_mode" setting for compatibility with legacy Python
-will use buildingplan to manage everything designated in a ``#build`` blueprint
+Quickfort. This setting has no effect on DFHack Quickfort, which will use
+buildingplan to manage everything designated in a ``#build`` blueprint
 regardless of the buildingplan UI settings.
 
-However, quickfort *does* use buildingplan's filters for each building type. For
+However, quickfort *does* use `buildingplan's filters <buildingplan-filters>`
-example, you can use the buildingplan UI to set the type of stone you want your
+for each building type. For example, you can use the buildingplan UI to set the
-walls made out of. Or you can specify that all buildingplan-managed tables must
+type of stone you want your walls made out of. Or you can specify that all
-be of Masterful quality. The current filter settings are saved with planned
+buildingplan-managed tables must be of Masterful quality. The current filter
-buildings when the ``#build`` blueprint is run. This means you can set the
+settings are saved with planned buildings when the ``#build`` blueprint is run.
-filters the way you want for one blueprint, run the blueprint, and then freely
+This means you can set the filters the way you want for one blueprint, run the
-change them again for the next blueprint, even if the first set of buildings
+blueprint, and then freely change them again for the next blueprint, even if the
-haven't been built yet.
+first set of buildings haven't been built yet.
 
 Note that buildings are still constructed immediately if you already have the
 materials. However, with buildingplan you now have the freedom to apply

plugins/buildingplan.cpp

@@ -954,7 +954,7 @@ static command_result buildingplan_cmd(color_ostream &out, vector <string> & par
             out.printerr(
                 "ERROR: A map must be loaded before you can read or set"
                 "buildingplan global settings. Try adding your"
-                "'buildingplan set' commands to the onMapLoad.init" "file.");
+                "'buildingplan set' commands to the onMapLoad.init file.\n");
             return CR_FAILURE;
         }
 
@@ -985,7 +985,7 @@ static command_result buildingplan_cmd(color_ostream &out, vector <string> & par
         }
         else
         {
-            out.printerr("ERROR: invalid syntax");
+            out.printerr("ERROR: invalid syntax\n");
         }
     }