Merge pull request #3011 from 1c-syntax/translations_docs-contributing-styleguide-md--develop_en

Translate 'docs/contributing/StyleGuide.md' in 'en'

Author: theshadowco

docs/en/contributing/StyleGuide.md

@@ -4,10 +4,29 @@ This document contains general guidelines for writing code in the BSL Language S
 
 Try to stick to them and the code review process will be simple.
 
-## General recommendations
+## Null values
 
 If a method can legally return `null`, it is recommended that you return `Optional<T>` instead of explicitly returning `null`. Exceptions (eg. high frequency or performance functions) are negotiated separately.
 
+The description of the `package-info.java` package must indicate that the NonNull API is used by default in the package.
+To do this, the annotation `@DefaultAnnotation(NonNull.class)` is added above the package name
+
+Example:
+```java
+// ...license...
+@DefaultAnnotation(NonNull.class)
+package com.github._1c_syntax.bsl.languageserver;
+
+import edu.umd.cs.findbugs.annotations.DefaultAnnotation;
+import edu.umd.cs.findbugs.annotations.NonNull;
+```
+
+To explicitly indicate that a method can accept or return `null`, use the annotation `@edu.umd.cs.findbugs.annotations.Nullable`.
+
+This avoids using the `@edu.umd.cs.findbugs.annotations.NonNull` annotation.
+
+The `null` control annotations from the `javax.annotations` or `jetbrains.annotations` packages are not allowed.
+
 ## Formatting
 
 1. All code in the modules should be automatically formatted.
@@ -56,6 +75,6 @@ To simplify the creation of a logger instance, it is recommended to use the `@lo
 1. Connecting new libraries to the implementation scope should be done carefully, with control over the increase in the size of the resulting jar file. If possible, "unnecessary" and unused sub-dependencies should be excluded through `exclude`.
 1. Explicit linking of the `com.google.guava`, `Google Collections` library or other parts of the Guava family of libraries is prohibited. **If absolutely necessary**, it is permissible to copy the implementation from `Guava` inside the BSL Language Server, subject to the terms of the Guava license. For everything else, there is Apache Commons.
 1. Import of `*.google.*` classes, as well as other parts of Guava libraries, is prohibited. With no exceptions.
-
+1. The `jsr305` package and its annotations should not be used in code. See section "Null values".
 
 > In the process...