Sort JSDoc parameter suggestions by argument position

Fixes #20183

When triggering completions after @param in a JSDoc comment,
parameter suggestions are now sorted by their position in the
function signature, so 'z' from foo(z, a) appears before 'a'.

Previously all parameters had the same sortText (LocationPriority),
causing them to be sorted alphabetically instead of by position.

Co-Authored-By: RoomWithOutRoof <RoomWithOutRoof@users.noreply.github.com>

Author: Jah-yee

src/services/jsDoc.ts

@@ -420,7 +420,7 @@ export function getJSDocParameterNameCompletions(tag: JSDocParameterTag): Comple
     const fn = jsdoc.parent;
     if (!isFunctionLike(fn)) return [];
 
-    return mapDefined(fn.parameters, param => {
+    return mapDefined(fn.parameters, (param, index) => {
         if (!isIdentifier(param.name)) return undefined;
 
         const name = param.name.text;
@@ -431,7 +431,9 @@ export function getJSDocParameterNameCompletions(tag: JSDocParameterTag): Comple
             return undefined;
         }
 
-        return { name, kind: ScriptElementKind.parameterElement, kindModifiers: "", sortText: Completions.SortText.LocationPriority };
+        // Sort by parameter position so that e.g. `@param z` from `foo(z, a)` comes before `@param a`
+        const sortText = `${index.toString().padStart(2, "0")}` as string & { __sortText: any };
+        return { name, kind: ScriptElementKind.parameterElement, kindModifiers: "", sortText };
     });
 }