Format using swift-format

Add `.swift-format` to the repo and format the repo with `swift-format`.

This commit does not add any automation to enforce formatting of sourcekit-lsp in CI. The goal of this commit is to get the majority of source changes out of the way so that the diff of actually enforcing formatting will have fewer changes or conflicts.

Sources/SKCore/CompilationDatabaseBuildSystem.swift

@@ -11,14 +11,14 @@
 //===----------------------------------------------------------------------===//
 
 import BuildServerProtocol
-import LanguageServerProtocol
-import LSPLogging
-import SKSupport
 import Dispatch
-import struct Foundation.URL
+import LSPLogging
+import LanguageServerProtocol
+import SKSupport
 
-import protocol TSCBasic.FileSystem
+import struct Foundation.URL
 import struct TSCBasic.AbsolutePath
+import protocol TSCBasic.FileSystem
 import var TSCBasic.localFileSystem
 
 /// A `BuildSystem` based on loading clang-compatible compilation database(s).
@@ -61,7 +61,7 @@ public actor CompilationDatabaseBuildSystem {
         let args = command.commandLine
         for i in args.indices.reversed() {
           if args[i] == "-index-store-path" && i != args.endIndex - 1 {
-            _indexStorePath = try? AbsolutePath(validating: args[i+1])
+            _indexStorePath = try? AbsolutePath(validating: args[i + 1])
             return _indexStorePath
           }
         }
@@ -93,10 +93,12 @@ extension CompilationDatabaseBuildSystem: BuildSystem {
       return nil
     }
     guard let db = database(for: url),
-          let cmd = db[url].first else { return nil }
+      let cmd = db[url].first
+    else { return nil }
     return FileBuildSettings(
       compilerArguments: Array(cmd.commandLine.dropFirst()),
-      workingDirectory: cmd.directory)
+      workingDirectory: cmd.directory
+    )
   }
 
   public func registerForChangeNotifications(for uri: DocumentURI, language: Language) async {