Don't ignore .vscode/extensions.json when developing third-party exercises

src/dev/new.rs

@@ -45,7 +45,7 @@ pub fn new(path: &Path, no_git: bool) -> Result<()> {
         bail!("`git init` didn't run successfully. See the error message above");
     }
 
-    write_rel_file(".gitignore", &dir_name, crate::init::GITIGNORE)?;
+    write_rel_file(".gitignore", &dir_name, GITIGNORE)?;
 
     create_rel_dir("exercises", &dir_name)?;
     create_rel_dir("solutions", &dir_name)?;
@@ -72,6 +72,13 @@ pub fn new(path: &Path, no_git: bool) -> Result<()> {
     Ok(())
 }
 
+pub const GITIGNORE: &[u8] = b".rustlings-state.txt
+Cargo.lock
+target
+.vscode
+!.vscode/extensions.json
+";
+
 const INFO_FILE_BEFORE_FORMAT_VERSION: &str =
     "# The format version is an indicator of the compatibility of third-party exercises with the
 # Rustlings program.

src/init.rs

@@ -55,7 +55,7 @@ pub fn init() -> Result<()> {
     Ok(())
 }
 
-pub const GITIGNORE: &[u8] = b".rustlings-state.txt
+const GITIGNORE: &[u8] = b".rustlings-state.txt
 Cargo.lock
 target
 .vscode