gdb: Improve doc strings

These are printed by gdb when requesting help for the corresponding
function or command, so phrase them such that they make sense in that
context.

MFC after:	1 week

3 files changed, 4 insertions, 6 deletions

diff --git a/sys/tools/gdb/acttrace.py b/sys/tools/gdb/acttrace.py
index 147effbbddf1..fdd18a4833cd 100644
--- a/sys/tools/gdb/acttrace.py
+++ b/sys/tools/gdb/acttrace.py
@@ -13,10 +13,8 @@ from pcpu import *
 
 class acttrace(gdb.Command):
     """
-    Register an acttrace command with gdb.
-
-    When run, acttrace prints the stack trace of all threads that were on-CPU
-    at the time of the panic.
+    Print the stack trace of all threads that were on-CPU at the time of
+    the panic.
     """
     def __init__(self):
         super(acttrace, self).__init__("acttrace", gdb.COMMAND_USER)
diff --git a/sys/tools/gdb/pcpu.py b/sys/tools/gdb/pcpu.py
index aadc4b2d42df..94c451e6eca5 100644
--- a/sys/tools/gdb/pcpu.py
+++ b/sys/tools/gdb/pcpu.py
@@ -9,7 +9,7 @@ from freebsd import *
 
 class pcpu(gdb.Function):
     """
-    Register a function to lookup PCPU and DPCPU variables by name.
+    A function to look up PCPU and DPCPU fields by name.
 
     To look up the value of the PCPU field foo on CPU n, use
     $PCPU("foo", n).  This works for DPCPU fields too.  If the CPU ID is
diff --git a/sys/tools/gdb/vnet.py b/sys/tools/gdb/vnet.py
index 36b4d512a3eb..5f416b2a515a 100644
--- a/sys/tools/gdb/vnet.py
+++ b/sys/tools/gdb/vnet.py
@@ -10,7 +10,7 @@ from freebsd import *
 
 class vnet(gdb.Function):
     """
-    Register a function to look up VNET variables by name.
+    A function to look up VNET variables by name.
 
     To look at the value of a VNET variable V_foo, print $V("foo").  The
     currently selected thread's VNET is used by default, but can be optionally