Teach Generated about Cargo lock files (#4100)

lib/linguist/generated.rb

@@ -57,6 +57,7 @@ module Linguist
       generated_net_designer_file? ||
       generated_net_specflow_feature_file? ||
       composer_lock? ||
+      cargo_lock? ||
       node_modules? ||
       go_vendor? ||
       npm_shrinkwrap_or_package_lock? ||
@@ -378,6 +379,13 @@ module Linguist
       !!name.match(/.\.zep\.(?:c|h|php)$/)
     end
 
+    # Internal: Is the blob a generated Rust Cargo lock file?
+    #
+    # Returns true or false.
+    def cargo_lock?
+      !!name.match(/Cargo\.lock/)
+    end
+
     # Is the blob a VCR Cassette file?
     #
     # Returns true or false

lib/linguist/languages.yml

@@ -4594,6 +4594,8 @@ TOML:
   type: data
   extensions:
   - ".toml"
+  filenames:
+  - Cargo.lock
   tm_scope: source.toml
   ace_mode: toml
   codemirror_mode: toml