fsmonitor: mark the built-in FSMonitor as experimental

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Documentation/config/core.txt

@@ -70,7 +70,8 @@ core.fsmonitor::
 See the "fsmonitor-watchman" section of linkgit:githooks[5].
 +
 Note: FSMonitor hooks (and this config setting) are ignored if the
-built-in FSMonitor is enabled (see `core.useBuiltinFSMonitor`).
+(experimental) built-in FSMonitor is enabled (see
+`core.useBuiltinFSMonitor`).
 
 core.fsmonitorHookVersion::
 	Sets the version of hook that is to be used when calling the
@@ -89,8 +90,9 @@ Note: FSMonitor hooks (and this config setting) are ignored if the
 built-in FSMonitor is enabled (see `core.useBuiltinFSMonitor`).
 
 core.useBuiltinFSMonitor::
-	If set to true, enable the built-in filesystem event watcher (for
-	technical details, see linkgit:git-fsmonitor--daemon[1]).
+	(EXPERIMENTAL) If set to true, enable the built-in filesystem
+	event watcher (for technical details, see
+	linkgit:git-fsmonitor--daemon[1]).
 +
 Like external (hook-based) FSMonitors, the built-in FSMonitor can speed up
 Git commands that need to refresh the Git index (e.g. `git status`) in a

Documentation/git-fsmonitor--daemon.txt

@@ -3,7 +3,7 @@ git-fsmonitor--daemon(1)
 
 NAME
 ----
-git-fsmonitor--daemon - Builtin file system monitor daemon
+git-fsmonitor--daemon - (EXPERIMENTAL) Builtin file system monitor daemon
 
 SYNOPSIS
 --------
@@ -20,6 +20,9 @@ SYNOPSIS
 DESCRIPTION
 -----------
 
+NOTE! This command is still only an experiment, subject to change dramatically
+(or even to be abandoned).
+
 Monitors files and directories in the working directory for changes using
 platform-specific file system notification facilities.