feat(bun): Detect bun using new text-format lockfile (#6441)

* Support bun text-format lockfile

Bun version 1.1.39 introduced a new plaintext lockfile. Currently it is opt-in only, but it will become the default in bun version 1.2.

* update docs

* update config schema

* update tests

.github/config-schema.json

@@ -87,6 +87,7 @@
       "default": {
         "detect_extensions": [],
         "detect_files": [
+          "bun.lock",
           "bun.lockb",
           "bunfig.toml"
         ],
@@ -2225,6 +2226,7 @@
         },
         "detect_files": {
           "default": [
+            "bun.lock",
             "bun.lockb",
             "bunfig.toml"
           ],