Rename Sentinel to lower case in error messages

Author: hrolfurgylfa

pyrefly/lib/alt/expr.rs

@@ -1834,7 +1834,7 @@ impl<'a, Ans: LookupAnswer> AnswersSolver<'a, Ans> {
                     errors,
                     arg.range(),
                     ErrorKind::InvalidSentinel,
-                    "Expected first argument of Sentinel to be a string literal".to_owned(),
+                    "Expected first argument of sentinel to be a string literal".to_owned(),
                 );
             }
         } else {
@@ -1873,7 +1873,7 @@ impl<'a, Ans: LookupAnswer> AnswersSolver<'a, Ans> {
                                 errors,
                                 kw.range,
                                 ErrorKind::InvalidSentinel,
-                                format!("Invalid type for Sentinel `repr` {got}"),
+                                format!("Invalid type for sentinel `repr` {got}"),
                             );
                         }
                     }
@@ -1882,7 +1882,7 @@ impl<'a, Ans: LookupAnswer> AnswersSolver<'a, Ans> {
                             errors,
                             kw.range,
                             ErrorKind::InvalidSentinel,
-                            format!("Unexpected keyword argument `{}` to Sentinel", id.id),
+                            format!("Unexpected keyword argument `{}` to sentinel", id.id),
                         );
                     }
                 },
@@ -1891,7 +1891,7 @@ impl<'a, Ans: LookupAnswer> AnswersSolver<'a, Ans> {
                         errors,
                         kw.range,
                         ErrorKind::InvalidSentinel,
-                        "Cannot pass unpacked keyword arguments to Sentinel".to_owned(),
+                        "Cannot pass unpacked keyword arguments to sentinel".to_owned(),
                     );
                 }
             }

pyrefly/lib/test/sentinel.rs

@@ -53,7 +53,7 @@ testcase!(
 from typing_extensions import Sentinel
 
 text = 5
-A = Sentinel("A", repr=text)  # E: Invalid type for Sentinel `repr` Literal[5]
+A = Sentinel("A", repr=text)  # E: Invalid type for sentinel `repr` Literal[5]
     "#,
 );
 
@@ -62,7 +62,7 @@ testcase!(
     r#"
 from typing_extensions import Sentinel
 
-A = Sentinel(name="A")  # E: Sentinel requires a name as the first argument # E: Unexpected keyword argument `name` to Sentinel
+A = Sentinel(name="A")  # E: Sentinel requires a name as the first argument # E: Unexpected keyword argument `name` to sentinel
     "#,
 );