Removed docker and swiftformat references (#1206)

Co-authored-by: Si Beaumont <simonjbeaumont@gmail.com> Co-authored-by: Konrad `ktoso` Malawski <konrad_malawski@apple.com>

Author: 3 people

.devcontainer/Dockerfile

@@ -1 +1 @@
-FROM swiftlang/swift:nightly-5.7-focal
+FROM swiftlang/swift:nightly-5.10-focal

.gitignore

@@ -36,3 +36,6 @@ Package.resolved
 
 # d files
 *.d
+
+# Visual Studio Code
+/.vscode

.licenseignore

@@ -6,7 +6,6 @@
 .mailfilter
 .mailmap
 .spi.yml
-.swiftformat
 .swift-format
 .swiftformatignore
 .editorconfig