Only sort completions by distance if partial is not empty

Otherwise, the shortest completions would always show up first, which is
not necessarily always desired. For example, if the user types a member
(.?) expression, it would be better to show relevant members on top
instead of those with the shortest name.

Author: fwcd

server/src/main/kotlin/org/javacs/kt/completion/Completions.kt

@@ -76,10 +76,9 @@ private fun elementCompletionItems(file: CompiledFile, cursor: Int, config: Comp
     val surroundingElement = completableElement(file, cursor) ?: return emptySequence()
     val completions = elementCompletions(file, cursor, surroundingElement)
 
-    val matchesName = completions
-        .filter { containsCharactersInOrder(name(it), partial, false) }
-        .sortedBy { stringDistance(name(it), partial) }
-    val visible = matchesName.filter(isVisible(file, cursor))
+    val matchesName = completions.filter { containsCharactersInOrder(name(it), partial, false) }
+    val sorted = matchesName.takeIf { partial.isNotEmpty() }?.sortedBy { stringDistance(name(it), partial) } ?: matchesName
+    val visible = sorted.filter(isVisible(file, cursor))
 
     return visible.map { completionItem(it, surroundingElement, file, config) }
 }