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/limio/limit.go

@@ -0,0 +1,31 @@
+package limio
+
+import "io"
+
+type limitedWriter struct {
+	W io.Writer
+	N int64
+}
+
+func (l *limitedWriter) Write(p []byte) (n int, err error) {
+	if l.N <= 0 {
+		return 0, io.ErrShortWrite
+	}
+	if int64(len(p)) > l.N {
+		p = p[0:l.N]
+		err = io.ErrShortWrite
+	}
+	n, er := l.W.Write(p)
+	if er != nil {
+		err = er
+	}
+	l.N -= int64(n)
+	return n, err
+}
+
+// LimitWriter works like io.LimitReader. It writes at most n bytes
+// to the underlying Writer. It returns io.ErrShortWrite if more than n
+// bytes are attempted to be written.
+func LimitWriter(w io.Writer, n int64) io.Writer {
+	return &limitedWriter{W: w, N: n}
+}