Use git log name-status in get last commit (#16059)

* Improve get last commit using git log --name-status

git log --name-status -c provides information about the diff between a
commit and its parents. Using this and adjusting the algorithm to use
the first change to a path allows for a much faster generation of commit
info.

There is a subtle change in the results generated but this will cause
the results to more closely match those from elsewhere.

Signed-off-by: Andrew Thornton <art27@cantab.net>

Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>
Co-authored-by: Lauris BH <lauris@nix.lv>

vendor/github.com/djherbis/buffer/list.go

@@ -0,0 +1,47 @@
+package buffer
+
+import "math"
+
+// List is a slice of Buffers, it's the backing for NewPartition
+type List []Buffer
+
+// Len is the sum of the Len()'s of the Buffers in the List.
+func (l *List) Len() (n int64) {
+	for _, buffer := range *l {
+		if n > math.MaxInt64-buffer.Len() {
+			return math.MaxInt64
+		}
+		n += buffer.Len()
+	}
+	return n
+}
+
+// Cap is the sum of the Cap()'s of the Buffers in the List.
+func (l *List) Cap() (n int64) {
+	for _, buffer := range *l {
+		if n > math.MaxInt64-buffer.Cap() {
+			return math.MaxInt64
+		}
+		n += buffer.Cap()
+	}
+	return n
+}
+
+// Reset calls Reset() on each of the Buffers in the list.
+func (l *List) Reset() {
+	for _, buffer := range *l {
+		buffer.Reset()
+	}
+}
+
+// Push adds a Buffer to the end of the List
+func (l *List) Push(b Buffer) {
+	*l = append(*l, b)
+}
+
+// Pop removes and returns a Buffer from the front of the List
+func (l *List) Pop() (b Buffer) {
+	b = (*l)[0]
+	*l = (*l)[1:]
+	return b
+}