Improve some typeahead matching behaviors

Summary:
Ref T8510. Sort prefix matches above non-prefix matches, so that "Ape Discovery" does not match "discovery" better than "Discovery".

Sort functions last.

Rename function internal strings so they don't get over-promoted the prefix-match rules.

Add kind of a hack to get "Project X" sorting above all the "Project X (Milestone 1)" results.

Test Plan:
Created "Ape Discovery", "Baboon Discovery", "Chimpanzee Discovery", etc.

Main project now sorts above milestones:

{F1681773}

Prefix matches now sort above other matches:

{F1681774}

Function results (rarely used) are now less prominent:

{F1681775}

Better function results here:

{F1681776}

More function results:

{F1681777}

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T8510

Differential Revision: https://secure.phabricator.com/D16094

webroot/rsrc/js/core/Prefab.js

@@ -184,11 +184,20 @@ JX.install('Prefab', {
       var priority_hits = {};
       var self_hits = {};
 
+      // We'll put matches where the user's input is a prefix of the name
+      // above mathches where that isn't true.
+      var prefix_hits = {};
+
       var tokens = this.tokenize(value);
+      var normal = this.normalize(value);
 
       for (var ii = 0; ii < list.length; ii++) {
         var item = list[ii];
 
+        if (this.normalize(item.name).indexOf(normal) === 0) {
+          prefix_hits[item.id] = true;
+        }
+
         for (var jj = 0; jj < tokens.length; jj++) {
           if (item.name.indexOf(tokens[jj]) === 0) {
             priority_hits[item.id] = true;
@@ -237,6 +246,10 @@ JX.install('Prefab', {
           return priority_hits[v.id] ? 1 : -1;
         }
 
+        if (prefix_hits[u.id] != prefix_hits[v.id]) {
+          return prefix_hits[v.id] ? 1 : -1;
+        }
+
         // Sort users ahead of other result types.
         if (u.priorityType != v.priorityType) {
           if (u.priorityType == 'user') {
@@ -247,6 +260,13 @@ JX.install('Prefab', {
           }
         }
 
+        // Sort functions after other result types.
+        var uf = (u.tokenType == 'function');
+        var vf = (v.tokenType == 'function');
+        if (uf != vf) {
+          return uf ? 1 : -1;
+        }
+
         return cmp(u, v);
       });
     },