chore: create examples/git-clang-format (#131)

This pull request introduces a new example project demonstrating the
usage of the `git-clang-format` command. The changes include
configuration files, documentation, and example source code.

### New example project for `git-clang-format`:

*
[`examples/git-clang-format/.clang-format`](diffhunk://#diff-3c15af9b07d3d1f0abe57fe105ed45cf8d43841bcd3f1c1cefd7f77b22c755d9R1-R2):
Added configuration file based on Google style with a column limit of
90.
*
[`examples/git-clang-format/README.md`](diffhunk://#diff-5bd7f2d85a02a051e388d92fc7cf99b27213d473269402d48097a537570609adR1-R132):
Added documentation explaining how to use `git-clang-format` with a
step-by-step guide and example outputs.
*
[`examples/git-clang-format/package.json`](diffhunk://#diff-4b5616cba814f4c7ca4ea49c77e8456efcc7931852306a3d899597507ad137b6R1-R13):
Added package configuration with scripts for modifying and formatting
the example source code.
*
[`examples/git-clang-format/src/main.c`](diffhunk://#diff-6818c1c5b98f76188b7448927e9e54053967986c07f5b1596cf3b60499b6578bR1-R13):
Added example source code file to demonstrate the formatting changes.
*
[`examples/git-clang-format/src/main_overwrite.txt`](diffhunk://#diff-9fd2872ab9b374d557d9ae0d2303c06f76fdf02502adeb21c238de284ee9e191R1-R13):
Added helper file used by the script to modify the example source code.

examples/git-clang-format/.clang-format

@@ -0,0 +1,2 @@
+BasedOnStyle: Google
+ColumnLimit: 90

examples/git-clang-format/README.md

@@ -0,0 +1,132 @@
+# `examples-git-clang-format`
+
+This example demonstrates the features of `git-clang-format` command (same as `git clang-format` command).
+
+Follow the guidelines below to see how `git-clang-format` works.
+
+## Getting Started
+
+Take a look at the `src/main.c` file in the `examples/git-clang-format` directory.
+
+Note that this file is not formatted according to the coding style configured in the `.clang-format` file at the root.
+
+In this scenario, what would happen if I add a space to line 9 of the `src/main.c` file, run `git add src/main.c`, and then execute `npx git-clang-format` (same as running `git clang-format`)?
+
+```c
+/* src/main.c */
+
+#include <stdio.h>
+
+int main(void) {
+  printf("Line 4");
+  printf("Line 5");
+  printf("Line 6");
+      printf("Line 7");
+  printf("Line 8");
+            printf("Line 9");
+  printf("Line 10");
+
+  return 0;
+}
+```
+
+### Step 1
+
+Run the following command to add a space to line 9 of the `src/main.c` file.
+
+#### Run from the Root
+
+```sh
+npm run add-a-space-to-line-9-of-main-c-file -w examples/git-clang-format
+```
+
+#### Navigate to the Directory and Run
+
+```sh
+cd examples/git-clang-format
+
+npm run add-a-space-to-line-9-of-main-c-file
+```
+
+---
+
+Now, you can see that the `src/main.c` file has been modified as shown below.
+
+```diff
+-            printf("Line 9");
++             printf("Line 9");
+```
+
+### Step 2
+
+Run the following command to add the modified `src/main.c` file to the staging area of Git.
+
+#### Run from the Root
+
+```sh
+npm run git-add -w examples/git-clang-format
+```
+
+#### Navigate to the Directory and Run
+
+```sh
+# cd examples/git-clang-format (You are already in the directory.)
+
+npm run git-add
+```
+
+---
+
+Now, you can see that the `src/main.c` file has been added to the staging area of Git.
+
+```txt
+Changes to be committed:
+  (use "git restore --staged <file>..." to unstage)
+        modified:   src/main.c
+```
+
+### Step 3
+
+Run the following command to run `git-clang-format` and check the result.
+
+#### Run from the Root
+
+```sh
+npm run git-clang-format -w examples/git-clang-format
+```
+
+#### Navigate to the Directory and Run
+
+```sh
+# cd examples/git-clang-format (You are already in the directory.)
+
+npm run git-clang-format
+```
+
+---
+
+If you run the command, it should produce an **error message** like the one below, since the modified `src/main.c` file is not formatted according to the coding style configured in the `.clang-format` file.
+
+```txt
+> examples-git-clang-format@1.2.3 git-clang-format
+> npx git-clang-format
+
+changed files:
+    examples/git-clang-format/src/main.c
+Process exited with code: 1
+```
+
+Check the 'Changes not staged for commit' section in Git using the `git status` command in the CLI and review the `src/main.c` file. The `git-clang-format` command should have fixed the code formatting according to the coding style configured in the `.clang-format` file.
+
+So, it is now properly formatted according to the configured coding style.
+
+```diff
+-             printf("Line 9");
++  printf("Line 9");
+```
+
+## Notable Points
+
+If you run the `npx clang-format src/main.c` command, it will format the entire `src/main.c` file according to the coding style configured in the `.clang-format` file.
+
+However, if you run the `npx clang-format src/main.c` command on a modified file, it will only format the changed lines of code. This is known as **Surgical Formatting**.

examples/git-clang-format/package.json

@@ -0,0 +1,13 @@
+{
+  "private": true,
+  "name": "examples-git-clang-format",
+  "version": "1.2.3",
+  "scripts": {
+    "add-a-space-to-line-9-of-main-c-file": "cat src/main_overwrite.txt > src/main.c",
+    "git-add": "git add src/main.c && git status",
+    "git-clang-format": "npx git-clang-format"
+  },
+  "dependencies": {
+    "clang-format-git": "^1.2.3"
+  }
+}

examples/git-clang-format/src/main.c

@@ -0,0 +1,13 @@
+#include <stdio.h>
+
+int main(void) {
+  printf("Line 4");
+  printf("Line 5");
+  printf("Line 6");
+      printf("Line 7");
+  printf("Line 8");
+            printf("Line 9");
+  printf("Line 10");
+
+  return 0;
+}

examples/git-clang-format/src/main_overwrite.txt

@@ -0,0 +1,13 @@
+#include <stdio.h>
+
+int main(void) {
+  printf("Line 4");
+  printf("Line 5");
+  printf("Line 6");
+      printf("Line 7");
+  printf("Line 8");
+             printf("Line 9");
+  printf("Line 10");
+
+  return 0;
+}