Add release notes about malformed patches from v5 not being applyable with v7

Resolves #588

Author: ExplodingCabbage

release-notes.md

@@ -49,7 +49,7 @@ This is a release containing many, *many* breaking changes. The objective of thi
   * The `fuzzFactor` now indicates the maximum [*Levenshtein* distance](https://en.wikipedia.org/wiki/Levenshtein_distance) that there can be between the context shown in a hunk and the actual file content at a location where we try to apply the hunk. (Previously, it represented a maximum [*Hamming* distance](https://en.wikipedia.org/wiki/Hamming_distance), meaning that a single insertion or deletion in the source file could stop a hunk from applying even with a high `fuzzFactor`.)
   * A hunk containing a deletion can now only be applied in a context where the line to be deleted actually appears verbatim. (Previously, as long as enough context lines in the hunk matched, `applyPatch` would apply the hunk anyway and delete a completely different line.)
   * The context line immediately before and immediately after an insertion must match exactly between the hunk and the file for a hunk to apply. (Previously this was not required.)
-- [#535](https://github.com/kpdecker/jsdiff/pull/535) **A bug in patch generation functions is now fixed** that would sometimes previously cause `\ No newline at end of file` to appear in the wrong place in the generated patch, resulting in the patch being invalid.
+- [#535](https://github.com/kpdecker/jsdiff/pull/535) **A bug in patch generation functions is now fixed** that would sometimes previously cause `\ No newline at end of file` to appear in the wrong place in the generated patch, resulting in the patch being invalid. **These invalid patches can also no longer be applied successfully with `applyPatch`.** (It was already the case that tools other than jsdiff, like GNU `patch`, would consider them malformed and refuse to apply them; versions of jsdiff with this fix now do the same thing if you ask them to apply a malformed patch emitted by jsdiff v5.)
 - [#535](https://github.com/kpdecker/jsdiff/pull/535) **Passing `newlineIsToken: true` to *patch*-generation functions is no longer allowed.** (Passing it to `diffLines` is still supported - it's only functions like `createPatch` where passing `newlineIsToken` is now an error.) Allowing it to be passed never really made sense, since in cases where the option had any effect on the output at all, the effect tended to be causing a garbled patch to be created that couldn't actually be applied to the source file.
 - [#539](https://github.com/kpdecker/jsdiff/pull/539) **`diffWords` now takes an optional `intlSegmenter` option** which should be an `Intl.Segmenter` with word-level granularity. This provides better tokenization of text into words than the default behaviour, even for English but especially for some other languages for which the default behaviour is poor.