Remove showcommands from docs

Test: none
Change-Id: Ia0be98049710175a0f3276841ef0c0bd2ccb60b6

Usage.txt

@@ -29,7 +29,7 @@ Ways to specify what to build:
   An alternative to setting $TARGET_PRODUCT and $TARGET_BUILD_VARIANT,
   which you may see in build servers, is to execute:
 
-    make PRODUCT-<product>-<variant>
+    m PRODUCT-<product>-<variant>
 
 
   A target may be a file path. For example, out/host/linux-x86/bin/adb .
@@ -46,6 +46,17 @@ Ways to specify what to build:
     files named Android.bp
       these files are defined in Blueprint syntax
 
+  During a build, a few log files are generated in ${OUT} (or ${DIST_DIR}/logs
+    for dist builds):
+
+    verbose.log.gz
+      every command run, along with its outputs. This is similar to the
+      previous `m showcommands` option.
+    error.log
+      list of actions that failed during the build, and their outputs.
+    soong.log
+      verbose debug information from soong_ui
+
   For now, the full (extremely large) compiled list of targets can be found
     (after running the build once), split among these two files:
 
@@ -57,8 +68,6 @@ Ways to specify what to build:
     tool here.
 
 Targets that adjust an existing build:
-  showcommands              Display the individual commands run to implement
-                            the build
   dist                      Copy into ${DIST_DIR} the portion of the build
                             that must be distributed
 
@@ -71,7 +80,7 @@ Variables
   Variables can either be set in the surrounding shell environment or can be
     passed as command-line arguments. For example:
       export I_AM_A_SHELL_VAR=1
-      I_AM_ANOTHER_SHELL_VAR=2 make droid I_AM_A_MAKE_VAR=3
+      I_AM_ANOTHER_SHELL_VAR=2 m droid I_AM_A_MAKE_VAR=3
   Here are some common variables and their meanings:
     TARGET_PRODUCT          The <product> to build # as described above
     TARGET_BUILD_VARIANT    The <variant> to build # as described above

core/build-system.html

@@ -147,12 +147,6 @@ <h3>Dependecies</h3>
 .c, .cpp, .h, .java, java libraries, etc., should all work without intervention
 in the Android.mk file.</p>
 
-<h3>Hiding command lines</h3>
-<p>The default of the build system will be to hide the command lines being
-executed for make steps.  It will be possible to override this by specifying
-the showcommands pseudo-target, and possibly by setting an environment
-variable.</p>
-
 <h3>Wildcard source files</h3>
 <p>Wildcarding source file will be discouraged.  It may be useful in some
 scenarios.  The default <code>$(wildcard *)</code> will not work due to the
@@ -326,19 +320,6 @@ <h3>More pseudotargets</h3>
 directory inside the current combo directory.  This is especially useful on the
 simulator and emulator, where the persistent data remains present between 
 builds.</li>
-<li><b>showcommands</b> - <code>showcommands</code> is a modifier target
-which causes the build system to show the actual command lines for the build
-steps, instead of the brief descriptions.  Most people don't like seeing the
-actual commands, because they're quite long and hard to read, but if you need
-to for debugging purposes, you can add <code>showcommands</code> to the list
-of targets you build.  For example <code>make showcommands</code> will build
-the default android configuration, and <code>make runtime showcommands</code>
-will build just the runtime, and targets that it depends on, while displaying
-the full command lines.  Please note that there are a couple places where the
-commands aren't shown here.  These are considered bugs, and should be fixed,
-but they're often hard to track down.  Please let
-<a href="mailto:android-build-team">android-build-team</a> know if you find
-any.</li>
 <li><b>LOCAL_MODULE</b> - Anything you specify as a <code>LOCAL_MODULE</code>
 in an Android.mk is made into a pseudotarget.  For example, <code>make
 runtime</code> might be shorthand for <code>make