Mark pixi lock files as generated (#7111)

Pixi is a cross-platform package manager for the conda ecosystem.
It uses a lockfile called pixi.lock, which should be counted as
generated code.

lib/linguist/generated.rb

@@ -70,6 +70,7 @@ def generated?
       poetry_lock? ||
       pdm_lock? ||
       uv_lock? ||
+      pixi_lock? ||
       esy_lock? ||
       npm_shrinkwrap_or_package_lock? ||
       pnpm_lock? ||
@@ -454,6 +455,13 @@ def uv_lock?
       !!name.match(/uv\.lock/)
     end
 
+    # Internal: Is the blob a generated pixi lock file?
+    #
+    # Returns true or false.
+    def pixi_lock?
+      !!name.match(/pixi\.lock/)
+    end
+
     # Internal: Is the blob a generated esy lock file?
     #
     # Returns true or false.

lib/linguist/languages.yml

@@ -8293,6 +8293,7 @@ YAML:
   - ".gemrc"
   - CITATION.cff
   - glide.lock
+  - pixi.lock
   - yarn.lock
   ace_mode: yaml
   codemirror_mode: yaml