[gjs] docs: Correct leftover mozjs38

[Philip Chimento <pchimento src gnome org>]

commit a4663543a1ff50605298b9aff9653b61bc8973e7
Author: Philip Chimento <philip chimento gmail com>
Date:   Thu Aug 24 20:35:15 2017 -0700

    docs: Correct leftover mozjs38
    
    mozjs38 -> mozjs52 in Hacking.md. Unreviewed.

 doc/Hacking.md |    8 +++++---
 1 files changed, 5 insertions(+), 3 deletions(-)
---
diff --git a/doc/Hacking.md b/doc/Hacking.md
index fd8a555..51c18c0 100644
--- a/doc/Hacking.md
+++ b/doc/Hacking.md
@@ -9,10 +9,10 @@ Even if your system includes a development package for mozjs, we
 recommend building it on JHBuild so that you can enable the debugging
 features. Add this to your JHBuild configuration file:
 ```python
-module_autogenargs['mozjs38'] = '--enable-debug'
+module_autogenargs['mozjs52'] = '--enable-debug'
 ```
 
-Make sure it is built first with `jhbuild build mozjs38`, otherwise
+Make sure it is built first with `jhbuild build mozjs52`, otherwise
 `jhbuild build gjs` will skip it if you have the system package
 installed.
 
@@ -36,9 +36,11 @@ mozjs, but you can grab them from your JHBuild copy of mozjs.
 After reaching a breakpoint in your program, type this to activate the
 pretty-printers:
 ```
-source ~/.cache/jhbuild/build/mozjs-38.0.0/js/src/shell/js-gdb.py
+source ~/.cache/jhbuild/build/mozjs-52.Y.Z/js/src/shell/js-gdb.py
 ```
 
+(replace `Y.Z` with mozjs's minor and micro version numbers)
+
 ## Checking Things More Thoroughly Before A Release ##
 
 ### Distcheck ###