Refactor README instructions structure

The commit involves a restructured list in the README to enhance readability. Instructions under 'Installation', 'Execution', and 'Integration with GitHub Actions' are now indented properly to be subordinate to their respective sections. The examples are also moved into a separate section for better clarity and organization.

Author: o0h

Diff for: README.md

@@ -25,22 +25,20 @@ The development of this tool was inspired by articles from :
 To use the PHP AST Check Diff Tool, follow these steps:
 
 1. Installation:
-- Run `composer require --dev o0h/ast-check-diff` to install the tool.
-
+   - Run `composer require --dev o0h/ast-check-diff` to install the tool.
 2. Execution:
-- Execute `vendor/bin/ast-check-diff check` to perform a comparison and output a Markdown document to standard output.
-- The `--head` and `--base` options can be passed via CLI to specify the source and destination of the comparison. Branch names, tags, or commit hashes can be used for this purpose.
+   - Execute `vendor/bin/ast-check-diff check` to perform a comparison and output a Markdown document to standard output.
+   - The `--head` and `--base` options can be passed via CLI to specify the source and destination of the comparison. Branch names, tags, or commit hashes can be used for this purpose.
+3. Integration with GitHub Actions:
+   - Integrating this tool with GitHub Actions for deep collaboration with pull requests is highly recommended.
+     - Example code of workflow: [GitHub Workflow](https://github.com/o0h/php-ast-check-diff/blob/main/.github/workflows/php-ast-check-diff.yml)
+     - Example of operation: [GitHub Pull Request Example](https://github.com/o0h/php-ast-check-diff/pull/5#issuecomment-1867274471)
+
 
- examples:
+examples:
 - `vendor/bin/ast-check-diff check ast-diff-check` : If the `--head` option is omitted, `HEAD` is implicitly specified, and if the `--base` option is omitted, the `main` branch is implicitly specified.
 - `vendor/bin/ast-check-diff check ast-diff-check --base HEAD@{3} --head HEAD~` : These comparisons are made by specifying pointers.
 - `vendor/bin/ast-check-diff check ast-diff-check --base cd2f816 --head 1a89b0c` : These comparisons are made by specifying specific commits.
-
-3. Integration with GitHub Actions:
- - Integrating this tool with GitHub Actions for deep collaboration with pull requests is highly recommended.
- - Example code of workflow: [GitHub Workflow](https://github.com/o0h/php-ast-check-diff/blob/main/.github/workflows/php-ast-check-diff.yml)
- - Example of operation: [GitHub Pull Request Example](https://github.com/o0h/php-ast-check-diff/pull/5#issuecomment-1867274471)
-
 ## Notes
 - This tool is intended for use with the latest PHP environments(8.3 or 8.2+).
 - Includes composer.lock: The project includes a composer.lock file.