Fix expressions docs highlight

Author: texodus

docs/docs/expressions.md

@@ -120,7 +120,7 @@ Perspective adds many of its own functions in addition to `ExprTK`'s standard
 ones, including common functions for `datetime` and `string` types such as
 `substring()`, `bucket()`, `day_of_week()`, etc. A full list of available
 functions is available in the
-[Expression Columns API](obj/perspective-viewer-exprtk).
+[Expression Columns API](../obj/perspective-viewer-exprtk).
 
 ## Examples
 

rust/perspective-viewer/src/less/column-selector.less

@@ -121,11 +121,10 @@
 
 :host {
     #add-expression {
-        border: var(--column-add--border, none);
+        border: var(--column-add--border, 1px solid transparent);
         min-height: 24px;
         flex-direction: row;
         font-size: 12px;
-        border: 1px solid transparent;
         background-color: #8b868045;
         border-radius: 2px;
         display: flex;