tools: bpftool: doc, fix incorrect text

Documentation about cgroup, feature, prog uses wrong header
'MAP COMMANDS' while listing commands. This patch corrects the header
in respective doc files.
Signed-off-by: Prashant Bhole <bhole_prashant_q7@lab.ntt.co.jp>
Acked-by: Yonghong Song <yhs@fb.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

tools/bpf/bpftool/Documentation/bpftool-cgroup.rst

@@ -17,8 +17,8 @@ SYNOPSIS
 	*COMMANDS* :=
 	{ **show** | **list** | **tree** | **attach** | **detach** | **help** }
 
-MAP COMMANDS
-=============
+CGROUP COMMANDS
+===============
 
 |	**bpftool** **cgroup { show | list }** *CGROUP*
 |	**bpftool** **cgroup tree** [*CGROUP_ROOT*]

tools/bpf/bpftool/Documentation/bpftool-feature.rst

@@ -16,8 +16,8 @@ SYNOPSIS
 
 	*COMMANDS* := { **probe** | **help** }
 
-MAP COMMANDS
-=============
+FEATURE COMMANDS
+================
 
 |	**bpftool** **feature probe** [*COMPONENT*] [**macros** [**prefix** *PREFIX*]]
 |	**bpftool** **feature help**

tools/bpf/bpftool/Documentation/bpftool-prog.rst

@@ -18,7 +18,7 @@ SYNOPSIS
 	{ **show** | **list** | **dump xlated** | **dump jited** | **pin** | **load**
 	| **loadall** | **help** }
 
-MAP COMMANDS
+PROG COMMANDS
 =============
 
 |	**bpftool** **prog { show | list }** [*PROG*]