Merge bitcoin/bitcoin#27205: doc: Show how less noisy clang-tidy output can be achieved

54c4d03 doc: Show how less noisy clang-tidy output can be achieved (TheCharlatan)

Pull request description:

  Adds a paragraph to the clang-tidy section explaining how to de-noise its output. By default clang-tidy will print errors arrising from included headers in leveldb and other dependencies. By passing `--enable-suppress-external-warnings` flag to configure, errors arising from external dependencies are suppressed. Additional errors arrising from internal dependencies such as leveldb are suppressed by passing the `src/.bear-tidy-config` configuration file to bear. This file includes exclusionary rules for leveldb.

ACKs for top commit:
  MarcoFalke:
    utACK 54c4d03

Tree-SHA512: c3dd8fb0600157582a38365a587e02e1d249fb246d6b8b4949a800fd05d3473dee49e2a4a556c60e51d6508feff810024e55fe09f5a0875f560fde30f3b6817c

Author: fanquake

doc/developer-notes.md

@@ -217,11 +217,14 @@ apt install clang-tidy bear clang
 Then, pass clang as compiler to configure, and use bear to produce the `compile_commands.json`:
 
 ```sh
-./autogen.sh && ./configure CC=clang CXX=clang++
-make clean && bear make -j $(nproc)     # For bear 2.x
-make clean && bear -- make -j $(nproc)  # For bear 3.x
+./autogen.sh && ./configure CC=clang CXX=clang++ --enable-suppress-external-warnings
+make clean && bear --config src/.bear-tidy-config -- make -j $(nproc)
 ```
 
+The output is denoised of errors from external dependencies and includes with
+`--enable-suppress-external-warnings` and `--config src/.bear-tidy-config`. Both
+options may be omitted to view the full list of errors.
+
 To run clang-tidy on all source files:
 
 ```sh