Fix rust-align-to-expr-after-brace, closes #11239.
Fix rust-align-to-expr-after-brace, closes #11239.

forward-to-word is undefined, and so Emacs would throw errors in
rust-align-to-expr-after-brace. This change yields the expected
behavior discussed in the issue.

mrBliss/rust-mode,rust-lang/rust-mode,Wilfred/rust-mode,rust-lang/rust-mode