Equal: ask for the second object again after a refused pick, name the kind it needs

A second object of the wrong kind (a circle after a line, a line after a
circle) or a pair that already carries Equal now reports and asks for the
second object again instead of ending the command. The mismatch message
names what the first object asks for — `Select a line segment, polyline
segment, text, MText, major or minor axis of ellipse or elliptical arc.`
after a length object, `Select a circle or arc.` after a radius object —
and the same-pick message carries the reference's double space.

Co-Authored-By: Claude Fable 5.1 <[email protected]>

src/modules/parametric/equal.rs

@@ -31,8 +31,12 @@ impl EqualConstraintCommand {
     pub const NO_OBJECT: &'static str = "No object found.";
     pub const INVALID_OBJECT: &'static str =
         "Invalid selection for Equal. Select a line, polyline segment, circle or arc.";
+    pub const INVALID_LENGTH_OBJECT: &'static str =
+        "Invalid selection for Equal. Select a line segment, polyline segment, text, MText, major or minor axis of ellipse or elliptical arc.";
+    pub const INVALID_RADIUS_OBJECT: &'static str =
+        "Invalid selection for Equal. Select a circle or arc.";
     pub const SAME_OBJECT: &'static str =
-        "The object or point is already selected. Select a different object or constraint point.";
+        "The object or point is already selected.  Select a different object or constraint point.";
 
     pub fn new() -> Self {
         Self {

src/modules/parametric/horizontal.rs

@@ -200,7 +200,7 @@ impl HorizontalConstraintCommand {
         if first.handle == second.handle && (first.point - second.point).length() <= 1.0e-9 {
             self.step = Step::SecondPoint(first);
             return CmdResult::ReportError(
-                "The object or point is already selected. Select a different object or constraint point."
+                "The object or point is already selected.  Select a different object or constraint point."
                     .to_string(),
             );
         }