Remove except in suspicious_else_formatting

This was causing two different ICEs in #3741.
The first was fixed in #3925.

The second one is fixed with this commit: We just don't `expect`
anymore. If the snippet doesn't contain an `else`, we stop emitting the
lint because it's not a suspiciously formatted else anyway.

clippy_lints/src/formatting.rs

@@ -165,8 +165,7 @@ fn check_else(cx: &EarlyContext<'_>, expr: &ast::Expr) {
             // the snippet should look like " else \n    " with maybe comments anywhere
             // it’s bad when there is a ‘\n’ after the “else”
             if let Some(else_snippet) = snippet_opt(cx, else_span) {
-                let else_pos = else_snippet.find("else").expect("there must be a `else` here");
-
+                if let Some(else_pos) = else_snippet.find("else") {
                     if else_snippet[else_pos..].contains('\n') {
                         let else_desc = if unsugar_if(else_).is_some() { "if" } else { "{..}" };
 
@@ -187,6 +186,7 @@ fn check_else(cx: &EarlyContext<'_>, expr: &ast::Expr) {
             }
         }
     }
+}
 
 fn has_unary_equivalent(bin_op: ast::BinOpKind) -> bool {
     // &, *, -