Update doc/guides/maintaining-types-for-nodejs.md

Co-authored-by: Mestery <[email protected]>

doc/guides/maintaining-types-for-nodejs.md

@@ -2,7 +2,7 @@
 
 While JavaScript is an untyped language, there are a number of complementary
 technologies like [TypeScript](https://www.typescriptlang.org/) and
-[flow](https://flow.org/) which allow developers to use types within their
+[Flow](https://flow.org/) which allow developers to use types within their
 JavaScript projects. While many people don't use types, there are enough
 who do that the project has agreed it's important to work towards having
 [suitable types for end-users](https://github.com/nodejs/node/blob/master/doc/contributing/technical-priorities.md#suitable-types-for-end-users).