[PATCH 2/2] diff: test and document -W interaction with -U<n>

@@ -88,6 +88,11 @@ endif::git-log[]
 --unified=<n>::
 	Generate diffs with <n> lines of context instead of
 	the usual three.
++
+Under `-W` generates diffs with at least <n> lines of context, if the
+number is lower than the context `-U<n>` would extend the diff to then
+`-U<n>` takes precedence.
+
 ifndef::git-format-patch[]
 	Implies `--patch`.
 endif::git-format-patch[]

@@ -763,6 +768,9 @@ endif::git-format-patch[]
 When showing the whole function for context the "@@" context line
 itself will always be empty, since the context that would otherwise be
 shown there will be the first line of the hunk being shown.
++
+See the documentation for `-U<n>` above for how the two options
+interact.
 
 ifndef::git-format-patch[]
 ifndef::git-log[]

@@ -98,6 +98,11 @@ test_diff_funcname () {
 		test_cmp W-U0-expected W-U0-actual
 	' &&
 
+	test_expect_success "$desc -W interaction with -U<n>" '
+		git diff -U9001 "$what" >W-U9001-diff &&
+		grep "^@@ -1," W-U9001-diff
+	' &&
+
 	test_expect_success "$desc (accumulated)" '
 		git diff -U1 "$what".acc >diff &&
 		last_diff_context_line diff >actual.lines &&