Adding checkstyle notes in README and contribution guidelines

Signed-off-by: Soby Chacko <[email protected]>

Author: sobychacko

CONTRIBUTING.adoc

@@ -7,7 +7,7 @@ what kind of changes are likely to be accepted; and what to expect from the Spri
 Please refer back to this document as a checklist before issuing any pull request; this will save time for everyone!
 
 == Code of Conduct
-This project adheres to the Contributor Covenant link:CODE_OF_CONDUCT.adoc[code of conduct].
+This project adheres to the Contributor Covenant https://github.com/spring-projects/spring-ai#coc-ov-file[code of conduct].
 By participating, you  are expected to uphold this code. Please report unacceptable behavior to
 [email protected].
 
@@ -133,6 +133,25 @@ This command, will provide the following output, which in this case shows a nice
 If you see intersecting lines, that usually means that you forgot to rebase you branch.
 As mentioned earlier, **please rebase against main** before issuing a pull request.
 
+== Enabling Checkstyle
+
+Checkstyles are currently disabled in the project.
+However, we encourage all PR contributors to run checkstyles by enabling them before submitting a PR.
+
+You can enable them by doing the following:
+
+```shell
+./mvnw clean package -DskipTests -Ddisable.checks=false
+```
+
+=== Source Code Style
+
+Spring AI source code checkstyle tries to follow the checkstyle guidelines used by the core Spring Framework project with some exceptions.
+The wiki pages
+[Code Style](https://github.com/spring-projects/spring-framework/wiki/Code-Style) and
+[IntelliJ IDEA Editor Settings](https://github.com/spring-projects/spring-framework/wiki/IntelliJ-IDEA-Editor-Settings)
+define the source file coding standards we use along with some IDEA editor settings we customize.
+
 == Mind the whitespace
 
 Please carefully follow the whitespace and formatting conventions already present in the framework.
@@ -265,4 +284,4 @@ Also by using specific
 https://help.github.com/en/github/managing-your-work-on-github/linking-a-pull-request-to-an-issue#linking-a-pull-request-to-an-issue-using-a-keyword[keywords]
 you can link to a GitHub issue like so:
 
-    Closes #10
+    Closes #10

README.md

@@ -115,23 +115,36 @@ To build the docs
 
 The docs are then in the directory `spring-ai-docs/target/antora/site/index.html`
 
+### Formatting the Source Code
+
 To reformat using the [java-format plugin](https://github.com/spring-io/spring-javaformat)
 ```shell
 ./mvnw spring-javaformat:apply
 ```
+### Updating License Headers
 
 To update the year on license headers using the [license-maven-plugin](https://oss.carbou.me/license-maven-plugin/#goals)
 ```shell
 ./mvnw license:update-file-header -Plicense
 ```
+### Javadocs
 
 To check javadocs using the [javadoc:javadoc](https://maven.apache.org/plugins/maven-javadoc-plugin/)
 ```shell
 ./mvnw javadoc:javadoc -Pjavadoc
 ```
+### Enabling Checkstyle
 
-To build with checkstyles enabled.
 Checkstyles are currently disabled, but you can enable them by doing the following:
+
 ```shell
 ./mvnw clean package -DskipTests -Ddisable.checks=false
 ```
+
+#### Source Code Style
+
+Spring AI source code checkstyle tries to follow the checkstyle guidelines used by the core Spring Framework project with some exceptions.
+The wiki pages
+[Code Style](https://github.com/spring-projects/spring-framework/wiki/Code-Style) and
+[IntelliJ IDEA Editor Settings](https://github.com/spring-projects/spring-framework/wiki/IntelliJ-IDEA-Editor-Settings)
+define the source file coding standards we use along with some IDEA editor settings we customize.