Rollup merge of #5415 - nickrtorres:master, r=flip1995

Add new lint for `Result<T, E>.map_or(None, Some(T))`

Fixes #5414

PR Checklist
---
- [x] Followed lint naming conventions (the name is a bit awkward, but it seems to conform)
- [x] Added passing UI tests (including committed .stderr file)
- [x] cargo test passes locally
- [x] Executed cargo dev update_lints
- [x] Added lint documentation
- [x] Run cargo dev fmt

`Result<T, E>` has an [`ok()`](https://doc.rust-lang.org/std/result/enum.Result.html#method.ok) method that adapts a `Result<T,E>` into an `Option<T>`.
It's possible to get around this adapter by writing `Result<T,E>.map_or(None, Some)`.

This lint is implemented as a new variant of the existing [`option_map_none` lint](https://github.com/rust-lang/rust-clippy/pull/2128)

clippy_lints/src/lib.rs

@@ -666,6 +666,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         &methods::OPTION_UNWRAP_USED,
         &methods::OR_FUN_CALL,
         &methods::RESULT_EXPECT_USED,
+        &methods::RESULT_MAP_OR_INTO_OPTION,
         &methods::RESULT_MAP_UNWRAP_OR_ELSE,
         &methods::RESULT_UNWRAP_USED,
         &methods::SEARCH_IS_SOME,
@@ -1281,6 +1282,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         LintId::of(&methods::OPTION_AS_REF_DEREF),
         LintId::of(&methods::OPTION_MAP_OR_NONE),
         LintId::of(&methods::OR_FUN_CALL),
+        LintId::of(&methods::RESULT_MAP_OR_INTO_OPTION),
         LintId::of(&methods::SEARCH_IS_SOME),
         LintId::of(&methods::SHOULD_IMPLEMENT_TRAIT),
         LintId::of(&methods::SINGLE_CHAR_PATTERN),
@@ -1459,6 +1461,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         LintId::of(&methods::NEW_RET_NO_SELF),
         LintId::of(&methods::OK_EXPECT),
         LintId::of(&methods::OPTION_MAP_OR_NONE),
+        LintId::of(&methods::RESULT_MAP_OR_INTO_OPTION),
         LintId::of(&methods::SHOULD_IMPLEMENT_TRAIT),
         LintId::of(&methods::STRING_EXTEND_CHARS),
         LintId::of(&methods::UNNECESSARY_FOLD),