Downgrade suspicious_op..._groupings to Nursery

This addresses rust-lang#6722.

Author: Michael Wright

clippy_lints/src/lib.rs

@@ -1408,7 +1408,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         LintId::of(slow_vector_initialization::SLOW_VECTOR_INITIALIZATION),
         LintId::of(stable_sort_primitive::STABLE_SORT_PRIMITIVE),
         LintId::of(strings::STRING_FROM_UTF8_AS_BYTES),
-        LintId::of(suspicious_operation_groupings::SUSPICIOUS_OPERATION_GROUPINGS),
         LintId::of(suspicious_trait_impl::SUSPICIOUS_ARITHMETIC_IMPL),
         LintId::of(suspicious_trait_impl::SUSPICIOUS_OP_ASSIGN_IMPL),
         LintId::of(swap::ALMOST_SWAPPED),
@@ -1562,7 +1561,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         LintId::of(returns::LET_AND_RETURN),
         LintId::of(returns::NEEDLESS_RETURN),
         LintId::of(single_component_path_imports::SINGLE_COMPONENT_PATH_IMPORTS),
-        LintId::of(suspicious_operation_groupings::SUSPICIOUS_OPERATION_GROUPINGS),
         LintId::of(tabs_in_doc_comments::TABS_IN_DOC_COMMENTS),
         LintId::of(to_digit_is_some::TO_DIGIT_IS_SOME),
         LintId::of(try_err::TRY_ERR),
@@ -1789,6 +1787,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         LintId::of(redundant_pub_crate::REDUNDANT_PUB_CRATE),
         LintId::of(regex::TRIVIAL_REGEX),
         LintId::of(strings::STRING_LIT_AS_BYTES),
+        LintId::of(suspicious_operation_groupings::SUSPICIOUS_OPERATION_GROUPINGS),
         LintId::of(transmute::USELESS_TRANSMUTE),
         LintId::of(use_self::USE_SELF),
     ]);

clippy_lints/src/suspicious_operation_groupings.rs

@@ -59,7 +59,7 @@ declare_clippy_lint! {
     /// }
     /// ```
     pub SUSPICIOUS_OPERATION_GROUPINGS,
-    style,
+    nursery,
     "groupings of binary operations that look suspiciously like typos"
 }