Fix URLs in the development docs

* Fix dead links where possible
* Use online instead of local links to the BeBook

Change-Id: I250117dcccc0026925c56545cca7e3b4467f2c78
Reviewed-on: https://review.haiku-os.org/c/811
Reviewed-by: Adrien Destugues <[email protected]>

docs/develop/kits/support/usecases/BStringUseCases.html

@@ -25,7 +25,7 @@ The document has the following sections:</P>
 memory for you so the buffer will always be "big enough" to contain the data.
 BString provides a number of charachter search, comparison, and manipulation functions in 
 a variety of flavors. The best source of information about the BString class can be found
-<A HREF="file:///boot/beos/documentation/Be%20Book/The%20Support%20Kit/String.html">here in the Be Book</A>.
+<A HREF="https://www.haiku-os.org/legacy-docs/bebook/BString.html">here in the Be Book</A>.
 </P>
 
 <A NAME="usecases"></A><H2>BString Use Cases:</H2>
@@ -58,4 +58,4 @@ parameter) of the string pointed by the pointer.</P></LI>
 
 
 </BODY>
-</HTML>
+</HTML>