Fix double space in pretty printed TryBlock

[dtolnay]

Follow-up to #92238 fixing one of the FIXMEs.

macro_rules! repro {
    ($expr:expr) => {
        stringify!($expr)
    };
}

fn main() {
    println!("{}", repro!(try {}));
}

Before: try  {}
After: try {}

The head helper already appends a space:

rust/compiler/rustc_ast_pretty/src/pprust/state.rs

Lines 654 to 664 in 2b67c30

	fn head<S: Into<Cow<'static, str>>>(&mut self, w: S) {
	let w = w.into();
	// Outer-box is consistent.
	self.cbox(INDENT_UNIT);
	// Head-box is inconsistent.
	self.ibox(w.len() + 1);
	// Keyword that starts the head.
	if !w.is_empty() {
	self.word_nbsp(w);
	}
	}

so doing head followed by space resulted in a double space:

rust/compiler/rustc_ast_pretty/src/pprust/state.rs

Lines 2241 to 2242 in 2b67c30

	self.head("try");
	self.space();

[rust-highfive]

r? @Mark-Simulacrum

(rust-highfive has picked a reviewer for you, use r? to override)

[Mark-Simulacrum]

@bors r+ rollup

[bors]

📌 Commit 2f25a4a has been approved by Mark-Simulacrum