fix .nvmrc versions

closes #10

Author: jhheider

fixtures/.nvmrc

@@ -0,0 +1 @@
+^20

src/sniff.test.ts

@@ -92,6 +92,7 @@ Deno.test("devenv.ts", async (runner) => {
           "pnpm.io@7.33.7",
         ],
         [".node-version", "nodejs.org@16.16.0"],
+        [".nvmrc", "nodejs.org^20"],
         ["python-version/std/.python-version", "python.org~3.10"],
         ["python-version/commented/.python-version", "python.org~3.11"],
         [".ruby-version", "ruby-lang.org@3.2.1"],

src/sniff.ts

@@ -162,7 +162,8 @@ export default async function (dir: Path) {
   async function version_file(path: Path, project: string) {
     let s = (await path.read()).trim();
     if (s.startsWith("v")) s = s.slice(1); // v prefix has no effect but is allowed
-    s = `${project}@${s}`;
+    if (s.match(/^[0-9]/)) s = `@${s}`; // bare versions are `@`ed
+    s = `${project}${s}`;
     pkgs.push(utils.pkg.parse(s));
   }