[docs] : fix typo 'then' => 'they' and re-generate 'reference.md'

Change-Id: I33d985775ecedd983f2a1a71742c180117465899
Reviewed-on: https://gn-review.googlesource.com/c/gn/+/5480
Reviewed-by: Scott Graham <scottmg@chromium.org>
Commit-Queue: Scott Graham <scottmg@chromium.org>

docs/reference.md

diff --git a/docs/reference.md b/docs/reference.md
index 5b43508..3a98061 100644
--- a/docs/reference.md
+++ b/docs/reference.md
@@ -3192,6 +3192,15 @@
 
         The command to run.
 
+    command_launcher  [string]
+        Valid for: all tools except "action" (optional)
+
+        The prefix with which to launch the command (e.g. the path to a Goma or
+        CCache compiler launcher).
+
+        Note that this prefix will not be included in the compilation database or
+        IDE files generated from the build.
+
     default_output_dir  [string with substitutions]
         Valid for: linker tools
 
@@ -5306,7 +5315,7 @@
   being relative to the current build file.
 
   libs and lib_dirs work differently than other flags in two respects.
-  First, then are inherited across static library boundaries until a
+  First, they are inherited across static library boundaries until a
   shared library or executable target is reached. Second, they are
   uniquified so each one is only passed once (the first instance of it
   will be the one used).
@@ -5348,7 +5357,7 @@
   library) containing the current target.
 
   libs and lib_dirs work differently than other flags in two respects.
-  First, then are inherited across static library boundaries until a
+  First, they are inherited across static library boundaries until a
   shared library or executable target is reached. Second, they are
   uniquified so each one is only passed once (the first instance of it
   will be the one used).

tools/gn/variables.cc

diff --git a/tools/gn/variables.cc b/tools/gn/variables.cc
index 43ef8a0..b35443d 100644
--- a/tools/gn/variables.cc
+++ b/tools/gn/variables.cc
@@ -1262,7 +1262,7 @@
 #define COMMON_LIB_INHERITANCE_HELP                                          \
   "\n"                                                                       \
   "  libs and lib_dirs work differently than other flags in two respects.\n" \
-  "  First, then are inherited across static library boundaries until a\n"   \
+  "  First, they are inherited across static library boundaries until a\n"   \
   "  shared library or executable target is reached. Second, they are\n"     \
   "  uniquified so each one is only passed once (the first instance of it\n" \
   "  will be the one used).\n"