[DOCS] Simple Grammar Style Coherency Fix

Question

### Documentation Type

Missing documentation (feature not documented)

### Documentation Location

https://github.com/anthropics/claude-code/blob/main/README.md

### Section/Topic

Get started -> Get Started

### Current Documentation

## Get started

### What's Wrong or Missing?

## Get started

Should become

## Get Started

To match the rest of the indentation level casing

### Suggested Improvement

Simple style matching fix

### Impact

Low - Minor confusion or inconvenience

### Additio