Stabilize suggestion applicability field in json output

src/librustc/session/config.rs

@@ -1316,8 +1316,6 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
     dep_info_omit_d_target: bool = (false, parse_bool, [TRACKED],
         "in dep-info output, omit targets for tracking dependencies of the dep-info files \
          themselves"),
-    suggestion_applicability: bool = (false, parse_bool, [UNTRACKED],
-        "include machine-applicability of suggestions in JSON output"),
     unpretty: Option<String> = (None, parse_unpretty, [UNTRACKED],
         "Present the input source, unstable (and less-pretty) variants;
         valid types are any of the types for `--pretty`, as well as:

src/librustc/session/mod.rs

@@ -1018,7 +1018,6 @@ pub fn build_session_with_codemap(
                     Some(registry),
                     codemap.clone(),
                     pretty,
-                    sopts.debugging_opts.suggestion_applicability,
                 ).ui_testing(sopts.debugging_opts.ui_testing),
             ),
             (config::ErrorOutputType::Json(pretty), Some(dst)) => Box::new(
@@ -1027,7 +1026,6 @@ pub fn build_session_with_codemap(
                     Some(registry),
                     codemap.clone(),
                     pretty,
-                    sopts.debugging_opts.suggestion_applicability,
                 ).ui_testing(sopts.debugging_opts.ui_testing),
             ),
             (config::ErrorOutputType::Short(color_config), None) => Box::new(