fix: use the same fold width for call hierarchy

Author: aminya

styles/atom-ide-outline.less

@@ -25,6 +25,8 @@
 @padding-h: 10px;
 @padding-v: 2px;
 
+@fold-width: 8px;
+
 .atom-ide-outline {
   display: flex;
   flex-direction: column;
@@ -41,8 +43,6 @@
       width: fit-content;
     }
 
-    @fold-width: 8px;
-
     --editor-tab-length: 4; // default
     --level-indent-size: 16px;
     --indent-level: 0; // initial

styles/call-hierarchy.less

@@ -62,6 +62,7 @@ atom-ide-outline-call-hierarchy-item {
   }
   > .call-hierarchy-exist-child-data > .icon::before {
     color: @text-color;
+    width: @fold-width;
   }
   atom-ide-outline-call-hierarchy-item {
     border-left: 1px solid @background-color-highlight;