patches: review fixes — eassert, blank lines, Texinfo doc

- nsterm.m: Remove 2 stray blank lines at start of
  ns_ax_event_is_line_nav_key body
- nsterm.m: Add eassert([NSThread isMainThread]) to ensureTextCache
  for explicit main-thread contract enforcement
- New 0002 patch: Texinfo section in doc/emacs/macos.texi documenting
  VoiceOver accessibility, Zoom tracking, completion announcements
- README.txt: Updated file listing and patch index

patches/0001-ns-implement-AXBoundsForRange-for-macOS-Zoom-cursor-.patch

@@ -786,12 +786,12 @@ index 932d209f..ea2de6f2 100644
 +static bool
 +ns_ax_event_is_line_nav_key (int *which)
 +{
- 
+-
 -#ifdef NS_IMPL_COCOA
 -  if (!canceled)
 -    font_panel_result = nil;
 -#endif
- 
+-
 -  result = font_panel_result;
 -  font_panel_result = nil;
 +  /* 1. Check Vthis_command for known navigation command symbols.
@@ -1431,6 +1431,7 @@ index 932d209f..ea2de6f2 100644
 +     below are therefore safe without @synchronized — only the
 +     write section at the end needs synchronization to protect
 +     against concurrent reads from AX server thread.  */
++  eassert ([NSThread isMainThread]);
 +  struct window *w = [self validWindow];
 +  if (!w || !WINDOW_LEAF_P (w))
 +    return;