add note about update-all-refs script, revert redundant pat to master

Author: DevinR528

doc/adding_lints.md

@@ -101,7 +101,9 @@ Once we are satisfied with the output, we need to run
 Please note that, we should run `TESTNAME=foo_functions cargo uitest`
 every time before running `tests/ui/update-all-references.sh`.
 Running `TESTNAME=foo_functions cargo uitest` should pass then. When we commit
-our lint, we need to commit the generated `.stderr` files, too.
+our lint, we need to commit the generated `.stderr` files, too. In general you
+should only run `tests/ui/update-all-references.sh` for the specific lint you are
+creating/editing.
 
 ## Rustfix tests
 

tests/ui/redundant_pattern_matching.rs

@@ -64,7 +64,6 @@ fn main() {
 
     let _ = does_something();
     let _ = returns_unit();
-    let _ = issue_5271();
 
     let opt = Some(false);
     let x = if let Some(_) = opt { true } else { false };