Fix typos and semantic errors in Serbian translation
Merge pull request #4927 from nikbas/serbian-message-translations

Fix typos and semantic errors in Serbian translation
changed syntax for referencing the guide in apidoc

New syntax:

```
[link to guide](guide:file-name.md)
[link to guide](guide:file-name.md#subsection)
```

fixes #4719
Update README.md
Update core-code-style.md

issue #4719
allow precision for binary type in MSSQL

fixes #4931
Fixes #3240: Added support for assigning an anonymous function to `yii\widgets\ActiveForm::fieldConfig`
Update guide pt-BR README file
Translate guide/start-hello into pt-BR
Small fix in pt-br guide/README
Fixes #3738: ActiveField custom error selector not functioning
Fixes #2380: `yii\widgets\ActiveForm` will register validation js even if there are not fields inside
Merge pull request #4934 from alanwillms/pt_br_start_hello

[ci skip] pt-BR start-hello
Fixed test breaks.
Fixes #4288: added a hint on how to specify console boolean values to the output of help
Simplified ArrayTrait::fields() default implementation since it works fine w/ just field names as values
Better alias check
Removed unused variable initialization
added missing serbian translations
Fixed phpdoc