chore: fix target in generated hg ignore file

Author: robjtede

Diff for: src/cargo/ops/cargo_new.rs

@@ -742,7 +742,7 @@ fn mk(config: &Config, opts: &MkOptions<'_>) -> CargoResult<()> {
     // Using the push method with multiple arguments ensures that the entries
     // for all mutually-incompatible VCS in terms of syntax are in sync.
     let mut ignore = IgnoreList::new();
-    ignore.push("/target", "^target/", "target");
+    ignore.push("/target", "^target$", "target");
     if !opts.bin {
         ignore.push("/Cargo.lock", "^Cargo.lock$", "Cargo.lock");
     }

Diff for: tests/testsuite/init/mercurial_autodetect/out/.hgignore

@@ -1,2 +1,2 @@
-^target/
+^target$
 ^Cargo.lock$

Diff for: tests/testsuite/init/simple_hg/out/.hgignore

@@ -1,2 +1,2 @@
-^target/
+^target$
 ^Cargo.lock$

Diff for: tests/testsuite/init/simple_hg_ignore_exists/out/.hgignore

@@ -2,5 +2,5 @@
 
 # Added by cargo
 
-^target/
+^target$
 ^Cargo.lock$