style(templates): add trailing newlines to styleguide templates

Ensure that styleguide templates comply with POSIX standards by ending with a newline character. This improves
compatibility with command-line tools and ensures consistent formatting for generated files.

Modified files:
- templates/code_styleguides/go.md
- templates/code_styleguides/html-css.md
- templates/code_styleguides/javascript.md
- templates/code_styleguides/python.md
- templates/code_styleguides/typescript.md

Signed-off-by: Nathen Harvey <nathenharvey@google.com>

Author: nathenharvey

templates/code_styleguides/go.md

@@ -45,4 +45,4 @@ This document summarizes key rules and best practices from the official "Effecti
 - **Explicit Error Handling:** Do not discard errors with the blank identifier (`_`). Check for errors explicitly.
 - **`panic`:** Reserved for truly exceptional, unrecoverable situations. Generally, libraries should not panic.
 
-*Source: [Effective Go](https://go.dev/doc/effective_go)*
+*Source: [Effective Go](https://go.dev/doc/effective_go)*

templates/code_styleguides/html-css.md

@@ -46,4 +46,4 @@ This document summarizes key rules and best practices from the Google HTML/CSS S
 
 **BE CONSISTENT.** When editing code, match the existing style.
 
-*Source: [Google HTML/CSS Style Guide](https://google.github.io/styleguide/htmlcssguide.html)*
+*Source: [Google HTML/CSS Style Guide](https://google.github.io/styleguide/htmlcssguide.html)*

templates/code_styleguides/javascript.md

@@ -48,4 +48,4 @@ This document summarizes key rules and best practices from the Google JavaScript
 - Use `@param`, `@return`, `@override`, `@deprecated`.
 - Type annotations are enclosed in braces (e.g., `/** @param {string} userName */`).
 
-*Source: [Google JavaScript Style Guide](https://google.github.io/styleguide/jsguide.html)*
+*Source: [Google JavaScript Style Guide](https://google.github.io/styleguide/jsguide.html)*

templates/code_styleguides/python.md

@@ -34,4 +34,4 @@ This document summarizes key rules and best practices from the Google Python Sty
 
 **BE CONSISTENT.** When editing code, match the existing style.
 
-*Source: [Google Python Style Guide](https://google.github.io/styleguide/pyguide.html)*
+*Source: [Google Python Style Guide](https://google.github.io/styleguide/pyguide.html)*

templates/code_styleguides/typescript.md

@@ -40,4 +40,4 @@ This document summarizes key rules and best practices from the Google TypeScript
 - **Redundancy:** **Do not declare types in `@param` or `@return` blocks** (e.g., `/** @param {string} user */`). This is redundant in TypeScript.
 - **Add Information:** Comments must add information, not just restate the code.
 
-*Source: [Google TypeScript Style Guide](https://google.github.io/styleguide/tsguide.html)*
+*Source: [Google TypeScript Style Guide](https://google.github.io/styleguide/tsguide.html)*