fix: include Type Checking section in DEVELOPMENT.md (#765)

## PR Checklist

- [x] Addresses an existing open issue: fixes #764
- [x] That issue was marked as [`status: accepting
prs`](https://github.com/JoshuaKGoldberg/create-typescript-app/issues?q=is%3Aopen+is%3Aissue+label%3A%22status%3A+accepting+prs%22)
- [x] Steps in
[CONTRIBUTING.md](https://github.com/JoshuaKGoldberg/create-typescript-app/blob/main/.github/CONTRIBUTING.md)
were taken

## Overview

Adds it in, always.

Author: JoshuaKGoldberg

src/steps/writing/creation/dotGitHub/createDevelopment.test.ts

@@ -122,6 +122,21 @@ describe("createDevelopment", () => {
 			This repository includes a [VS Code launch configuration](https://code.visualstudio.com/docs/editor/debugging) for debugging unit tests.
 			To launch it, open a test file, then run _Debug Current Test File_ from the VS Code Debug panel (or press F5).
 
+			## Type Checking
+
+			You should be able to see suggestions from [TypeScript](https://typescriptlang.org) in your editor for all open files.
+
+			However, it can be useful to run the TypeScript command-line (\`tsc\`) to type check all files in \`src/\`:
+
+			\`\`\`shell
+			pnpm tsc
+			\`\`\`
+
+			Add \`--watch\` to keep the type checker running in a watch mode that updates the display as you save files:
+
+			\`\`\`shell
+			pnpm tsc --watch
+			\`\`\`
 			"
 		`);
 	});
@@ -209,6 +224,21 @@ describe("createDevelopment", () => {
 			This repository includes a [VS Code launch configuration](https://code.visualstudio.com/docs/editor/debugging) for debugging unit tests.
 			To launch it, open a test file, then run _Debug Current Test File_ from the VS Code Debug panel (or press F5).
 
+			## Type Checking
+
+			You should be able to see suggestions from [TypeScript](https://typescriptlang.org) in your editor for all open files.
+
+			However, it can be useful to run the TypeScript command-line (\`tsc\`) to type check all files in \`src/\`:
+
+			\`\`\`shell
+			pnpm tsc
+			\`\`\`
+
+			Add \`--watch\` to keep the type checker running in a watch mode that updates the display as you save files:
+
+			\`\`\`shell
+			pnpm tsc --watch
+			\`\`\`
 			"
 		`);
 	});

src/steps/writing/creation/dotGitHub/createDevelopment.ts

@@ -103,5 +103,20 @@ This repository includes a [VS Code launch configuration](https://code.visualstu
 To launch it, open a test file, then run _Debug Current Test File_ from the VS Code Debug panel (or press F5).
 `
 }
+## Type Checking
+
+You should be able to see suggestions from [TypeScript](https://typescriptlang.org) in your editor for all open files.
+
+However, it can be useful to run the TypeScript command-line (\`tsc\`) to type check all files in \`src/\`:
+
+\`\`\`shell
+pnpm tsc
+\`\`\`
+
+Add \`--watch\` to keep the type checker running in a watch mode that updates the display as you save files:
+
+\`\`\`shell
+pnpm tsc --watch
+\`\`\`
 `;
 }