libutil: Format lru-cache.hh

Rip off the band-aid for further refactors. The diff is
very small, so it makes to get it out of the way first.

maintainers/flake-module.nix

@@ -360,7 +360,6 @@
               ''^src/libutil/linux/namespaces\.cc$''
               ''^src/libutil/logging\.cc$''
               ''^src/libutil/include/nix/util/logging\.hh$''
-              ''^src/libutil/include/nix/util/lru-cache\.hh$''
               ''^src/libutil/memory-source-accessor\.cc$''
               ''^src/libutil/include/nix/util/memory-source-accessor\.hh$''
               ''^src/libutil/include/nix/util/pool\.hh$''

src/libutil/include/nix/util/lru-cache.hh

@@ -25,21 +25,28 @@ private:
     using Data = std::map<Key, std::pair<LRUIterator, Value>>;
     using LRU = std::list<typename Data::iterator>;
 
-    struct LRUIterator { typename LRU::iterator it; };
+    struct LRUIterator
+    {
+        typename LRU::iterator it;
+    };
 
     Data data;
     LRU lru;
 
 public:
 
-    LRUCache(size_t capacity) : capacity(capacity) { }
+    LRUCache(size_t capacity)
+        : capacity(capacity)
+    {
+    }
 
     /**
      * Insert or upsert an item in the cache.
      */
     void upsert(const Key & key, const Value & value)
     {
-        if (capacity == 0) return;
+        if (capacity == 0)
+            return;
 
         erase(key);
 
@@ -64,7 +71,8 @@ public:
     bool erase(const Key & key)
     {
         auto i = data.find(key);
-        if (i == data.end()) return false;
+        if (i == data.end())
+            return false;
         lru.erase(i->second.first.it);
         data.erase(i);
         return true;
@@ -77,7 +85,8 @@ public:
     std::optional<Value> get(const Key & key)
     {
         auto i = data.find(key);
-        if (i == data.end()) return {};
+        if (i == data.end())
+            return {};
 
         /**
          * Move this item to the back of the LRU list.