feat: Update for deprecated @ syntax in mkosi files

docs/SYSTEMD-SYNTAX.md

@@ -31,3 +31,26 @@ Key=line1
  line2
 Key2=val # Comment
 ```
+
+### Deprecated `@` "Default Value" Syntax
+
+Old:
+
+> <https://github.com/systemd/mkosi/blob/8aefea6923dd049d060eea7e88f9054b674b432e/mkosi/resources/mkosi.md>
+>
+> If a setting's name in the configuration file is prefixed with `@`, 
+> it configures the default value used for that setting if no explicit default value is set. 
+> This can be used to set custom default values in configuration files that can still be overridden by
+> specifying the setting explicitly via the CLI.
+
+
+They removed it in the commit [1b8f7f240dfdc85bc7bdf2b3aea3c590d2203eba](https://github.com/systemd/mkosi/commit/1b8f7f240dfdc85bc7bdf2b3aea3c590d2203eba):
+
+> Note that settings configured via the command line always override
+> settings configured via configuration files. If the same setting is
+> configured more than once via configuration files, later assignments
+> override earlier assignments except for settings that take a collection
+> of values. Also, settings read from `mkosi.local.conf` will override
+> settings from configuration files that are parsed later but not settings
+> specified on the CLI.
+

src/vscode-lint.ts

@@ -112,7 +112,8 @@ export class SystemdLint implements CodeActionProvider {
         const { customDirectiveKeys, customDirectiveRegexps } = config;
         const fileType = this.documents.getType(document);
 
-        const opts: CommonOptions = { mkosi: fileType === SystemdFileType.mkosi };
+        const mkosiMode = fileType === SystemdFileType.mkosi
+        const opts: CommonOptions = { mkosi: mkosiMode };
         const { tokens } = tokenizer(document.getText(), opts);
         const dirs = getDirectivesFromTokens(tokens);
         // console.log("lintDocument", dirs);
@@ -123,8 +124,12 @@ export class SystemdLint implements CodeActionProvider {
         dirs.forEach((it) => {
             if (!it.key) return;
 
-            const directiveName = it.key.trim();
+            let directiveName = it.key.trim();
+            // compatible with the old mkosi `@` syntax (they have removed it)
+            if (mkosiMode && directiveName.startsWith('@'))
+                directiveName = directiveName.slice(1);
             const directiveNameLC = directiveName.toLowerCase();
+
             //#region lint by name
             if (directiveNameLC.startsWith("x-")) return;
             if (directiveNameLC.startsWith("-")) return;