Fix type for path-has-extension?.

Closes #1459.

Author: samth

typed-racket-lib/typed-racket/base-env/base-env.rkt

@@ -2889,7 +2889,7 @@
 [simple-form-path (-Pathlike . -> . -Path)]
 [normalize-path (cl->* (-Pathlike [-Pathlike] . ->opt . -Path))]
 [path-get-extension (-SomeSystemPathlike . -> . (-opt -Bytes))]
-[path-has-extension? (-SomeSystemPathlike (Un -String -Bytes) . -> . (-opt -Bytes))]
+[path-has-extension? (-SomeSystemPathlike (Un -String -Bytes) . -> . B)]
 [filename-extension (-SomeSystemPathlike . -> . (-opt -Bytes))]
 [file-name-from-path (-Pathlike . -> . (-opt -Path))]
 [path-only (-SomeSystemPathlike . -> . (-opt -Path))]

typed-racket-test/unit-tests/typecheck-tests.rkt

@@ -1632,6 +1632,7 @@
 
         (tc-e (resolve-path "foo") -Path)
         (tc-e (expand-user-path "foo") -Path)
+        (tc-e (path-has-extension? "a.git" ".git") -Boolean)
 
         ;;String Tests
         (tc-e (string? "a") #:ret (tc-ret -Boolean -true-propset))