doc: log, gitk: line-log arguments must exist in starting revision

The line number, regex or offset parameters <start> and <end> in
`git log -L <start>,<end>:<file>`, or the function name regex in
`git log -L :<funcname>:<file>` must exist in the starting
revision, or else the command exits with a fatal error.

This is not obvious in the documentation, so add a note to that
effect.

Signed-off-by: Philippe Blain <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: phil-blain

Documentation/git-log.txt

@@ -76,7 +76,8 @@ produced by `--stat`, etc.
 	(or the function name regex <funcname>) within the <file>.  You may
 	not give any pathspec limiters.  This is currently limited to
 	a walk starting from a single revision, i.e., you may only
-	give zero or one positive revision arguments.
+	give zero or one positive revision arguments, and
+	<start> and <end> (or <funcname>) must exist in the starting revision.
 	You can specify this option more than once. Implies `--patch`.
 	Patch output can be suppressed using `--no-patch`, but other diff formats
 	(namely `--raw`, `--numstat`, `--shortstat`, `--dirstat`, `--summary`,

Documentation/gitk.txt

@@ -105,7 +105,8 @@ linkgit:git-rev-list[1] for a complete list.
 	(or the function name regex <funcname>) within the <file>.  You may
 	not give any pathspec limiters.  This is currently limited to
 	a walk starting from a single revision, i.e., you may only
-	give zero or one positive revision arguments.
+	give zero or one positive revision arguments, and
+	<start> and <end> (or <funcname>) must exist in the starting revision.
 	You can specify this option more than once. Implies `--patch`.
 	Patch output can be suppressed using `--no-patch`, but other diff formats
 	(namely `--raw`, `--numstat`, `--shortstat`, `--dirstat`, `--summary`,