Add ripgrep installation and usage guide for macOS

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Co-Authored-By: Claude <noreply@anthropic.com>

Author: kfet

shell/ripgrep.md

@@ -0,0 +1,20 @@
+# Installing and Using Ripgrep on macOS
+
+## Installation
+
+```bash
+brew install ripgrep
+```
+
+## Basic Usage
+
+Search for pattern in current directory:
+```bash
+rg "pattern"
+```
+
+Search in specific file or directory:
+```bash
+rg "pattern" path/to/file
+rg "pattern" path/to/directory
+```