strbuf.h: remove a tad stale docs-in-comment and reference api-doc instead

Signed-off-by: Michael Witten <mfwitten@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

strbuf.h

@@ -1,42 +1,7 @@
 #ifndef STRBUF_H
 #define STRBUF_H
 
-/*
- * Strbuf's can be use in many ways: as a byte array, or to store arbitrary
- * long, overflow safe strings.
- *
- * Strbufs has some invariants that are very important to keep in mind:
- *
- * 1. the ->buf member is always malloc-ed, hence strbuf's can be used to
- *    build complex strings/buffers whose final size isn't easily known.
- *
- *    It is NOT legal to copy the ->buf pointer away.
- *    `strbuf_detach' is the operation that detaches a buffer from its shell
- *    while keeping the shell valid wrt its invariants.
- *
- * 2. the ->buf member is a byte array that has at least ->len + 1 bytes
- *    allocated. The extra byte is used to store a '\0', allowing the ->buf
- *    member to be a valid C-string. Every strbuf function ensures this
- *    invariant is preserved.
- *
- *    Note that it is OK to "play" with the buffer directly if you work it
- *    that way:
- *
- *    strbuf_grow(sb, SOME_SIZE);
- *       ... Here, the memory array starting at sb->buf, and of length
- *       ... strbuf_avail(sb) is all yours, and you are sure that
- *       ... strbuf_avail(sb) is at least SOME_SIZE.
- *    strbuf_setlen(sb, sb->len + SOME_OTHER_SIZE);
- *
- *    Of course, SOME_OTHER_SIZE must be smaller or equal to strbuf_avail(sb).
- *
- *    Doing so is safe, though if it has to be done in many places, adding the
- *    missing API to the strbuf module is the way to go.
- *
- *    XXX: do _not_ assume that the area that is yours is of size ->alloc - 1
- *         even if it's true in the current implementation. Alloc is somehow a
- *         "private" member that should not be messed with.
- */
+/* See Documentation/technical/api-strbuf.txt */
 
 #include <assert.h>