Make unexpected token formatting clearer (#243)

Symbols are now be surrounded by single quotes, to set them off more
clearly.

src/integration.rs

@@ -1274,7 +1274,7 @@ integration_test! {
 }
 
 integration_test! {
-  name:     unexpected_token,
+  name:     unexpected_token_in_dependency_position,
   justfile: "foo: 'bar'",
   args:     ("foo"),
   stdout:   "",
@@ -1286,6 +1286,18 @@ integration_test! {
   status:   EXIT_FAILURE,
 }
 
+integration_test! {
+  name:     unexpected_token_after_name,
+  justfile: "foo 'bar'",
+  args:     ("foo"),
+  stdout:   "",
+  stderr:   "error: Expected name, '+', ':', or '=', but found raw string
+  |
+1 | foo 'bar'
+  |     ^^^^^
+",
+  status:   EXIT_FAILURE,
+}
 
 integration_test! {
   name:     self_dependency,

src/lib.rs

@@ -1493,19 +1493,19 @@ impl Display for TokenKind {
   fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
     write!(f, "{}", match *self {
       Backtick           => "backtick",
-      Colon              => "\":\"",
+      Colon              => "':'",
       Comment            => "comment",
       Dedent             => "dedent",
       Eof                => "end of file",
       Eol                => "end of line",
-      Equals             => "\"=\"",
+      Equals             => "'='",
       Indent             => "indent",
-      InterpolationEnd   => "}}",
+      InterpolationEnd   => "'}}'",
-      InterpolationStart => "{{",
+      InterpolationStart => "'{{'",
       Line               => "command",
       Name               => "name",
-      Plus               => "\"+\"",
+      Plus               => "'+'",
-      At                 => "\"@\"",
+      At                 => "'@'",
       StringToken        => "string",
       RawString          => "raw string",
       Text               => "command text",