Small fixes to platform packet documentation

[jasonmolenda]

Summary

I have a standalone implementation of the lldb platform packets for Darwin systems, and in the process of updating it to match the fixes from Michał in https://reviews.llvm.org/D107475 , I found a few places where the documentation needed to be updated to match lldb/gdb's actual behavior.

[jasonmolenda]

FWIW I started updating my implementation by reading through all the changes to the docs, and implementing them. Then I went back and looked at the patches and found some small changes that were made but without documentation being updated, or the documentation not being specific about expected details.

lldb/docs/lldb-platform-packets.txt

 //  receive: qPlatform_mkdir:000001fd,2f746d702f6131
 //  send:    F0
 //
 //  request packet has the fields:
 //     1. mode bits in base 16
 //     2. file path in ascii-hex encoding
 //
 //  response is F followed by the return value of the mkdir() call,
-//  base 10 encoded.
+//  base 16 encoded.
 
 //----------------------------------------------------------------------
 // qPlatform_shell:
 //
 // BRIEF
 //   Run a shell command on the target system, return the output.
 //
 // EXAMPLE

 //   Get the size of a file on the target system, filename in ASCII hex.
 //
 // EXAMPLE
 // 
 //  receive: vFile:size:2f746d702f61
 //  send:    Fc008
 //
 //  response is "F" followed by the file size in base 16.
-//  "F-1,errno" with the errno if an error occurs.
+//  "F-1,errno" with the errno if an error occurs, base 16.
 
 
 //----------------------------------------------------------------------
 // vFile:mode:
 //
 // BRIEF
 //   Get the mode bits of a file on the target system, filename in ASCII hex.
 //
 // EXAMPLE
 // 
 //  receive: vFile:mode:2f746d702f61
 //  send:    F1ed
 //
 //  response is "F" followed by the mode bits in base 16, this 0x1ed would 
 //  correspond to 0755 in octal.  
-//  "F-1,errno" with the errno if an error occurs.
+//  "F-1,errno" with the errno if an error occurs, base 16.
 
 //----------------------------------------------------------------------
 // vFile:unlink:
 //
 // BRIEF
 //   Remove a file on the target system.
 //
 // EXAMPLE
 // 
 //  receive: vFile:unlink:2f746d702f61
 //  send:    F0
 //
 //  Argument is a file path in ascii-hex encoding.
-//  Response is "F" plus the return value of unlink(), base 10 encoding.
+//  Response is "F" plus the return value of unlink(), base 16 encoding.
+//  Return value may optionally be followed by a comma and the base16
+//  value of errno if unlink failed.
 
 //----------------------------------------------------------------------
 // vFile:symlink:
 //
 // BRIEF
 //   Create a symbolic link (symlink, soft-link) on the target system.
 //
 // EXAMPLE
 // 
 //  receive: vFile:symlink:<SRC-FILE>,<DST-NAME>
 //  send:    F0,0
 //
 //  Argument file paths are in ascii-hex encoding.
-//  Response is "F" plus the return value of symlink(), base 10 encoding, twice.
+//  Response is "F" plus the return value of symlink(), base 16 encoding, 
+//  optionally followed by the value of errno if it failed, also base 16.
 
 //----------------------------------------------------------------------
 // vFile:chmod:
 // qPlatform_chmod:
 //
 // BRIEF
 //   Change the permission mode bits on a file on the target
 //
 // EXAMPLE
 // 
 //  receive: vFile:chmod:180,2f746d702f61
 //  send:    F0
 //
 //  Arguments are the mode bits to set, base 16, and a file path in 
 //  ascii-hex encoding.
-//  Response is "F" plus the return value of chmod(), base 10 encoding.
+//  Response is "F" plus the return value of chmod(), base 16 encoding.
 //
 //  I don't know why there are two packets for the same thing, v.
 //  vFile:chmod:.
 
 //----------------------------------------------------------------------
 // vFile:chmod:
 //
 // BRIEF

 //  request packet has the fields:
 //     1. ASCII hex encoded filename
 //     2. flags passed to the open call, base 16.
 //        Note that these are not the oflags that open(2) takes, but
 //        are the constant values in enum OpenOptions from lldb's File.h
 //     3. mode bits, base 16
 //  
 //  response is F followed by the opened file descriptor in base 16.
-//  "F-1,errno" with the errno if an error occurs.
+//  "F-1,errno" with the errno if an error occurs, base 16.
 //
 //----------------------------------------------------------------------
 // vFile:close:
 //
 // BRIEF
 //   Close a previously opened file descriptor.
 //
 // EXAMPLE
 // 
 //  receive: vFile:close:7
 //  send:    F0
 //
 //  File descriptor is in base 16.
-//  "F-1,errno" with the errno if an error occurs.
+//  "F-1,errno" with the errno if an error occurs,
+//  errno is base 16.
 
 
 //----------------------------------------------------------------------
 // vFile:pread:
 //
 // BRIEF
 //   Read data from an opened file descriptor.
 //