update text for removed pages; update site-nav

Pages that exist solely to prevent 404s shouldn't be in site-nav. Reordered links in site-nav so that they're properly alphabetized.

_pages/en_US/dsidumper.txt

@@ -2,4 +2,5 @@
 title: "DSiDumper"
 ---
 
-This guide is no longer relevant. Please start from the [home page](/).
+This page has been removed because the method used is outdated. Please follow a modern method linked on the [Get Started](get-started) page.
+{: .notice--warning}

_pages/en_US/homebrew-launcher-(steelhax).txt

@@ -2,4 +2,5 @@
 title: "Homebrew Launcher (Steelhax)"
 ---
 
-This guide is no longer relevant. Please start from the [home page](/).
+This page has been removed because the method used is outdated. Please follow a modern method linked on the [Get Started](get-started) page.
+{: .notice--warning}

_pages/en_US/site-navigation.txt

@@ -21,7 +21,6 @@ sitemap: false
 + [Cartridge Update](cart-update)
 + [Credits](credits)
 + [CTRTransfer](ctrtransfer)
-+ [DSiWare Dumper](dsidumper)
 + [Donations](donations)
 + [F3 (Linux)](f3-(linux))
 + [F3X (Mac)](f3x-(mac))
@@ -32,9 +31,6 @@ sitemap: false
 + [Flashing ntrboot (3DS Multi System)](flashing-ntrboot-(3ds-multi-system))
 + [Flashing ntrboot (DSi)](flashing-ntrboot-(dsi))
 + [Flashing ntrboot (NDS)](flashing-ntrboot-(nds))
-+ [Formatting SD (Linux)](formatting-sd-(linux))
-+ [Formatting SD (Mac)](formatting-sd-(mac))
-+ [Formatting SD (Windows)](formatting-sd-(windows))
 + [Get Started](get-started)
 + [GodMode9 Usage](godmode9-usage)
 + [H2testw (Windows)](h2testw-(windows))
@@ -42,23 +38,22 @@ sitemap: false
 + [Homebrew Launcher (Alternatives)](homebrew-launcher-(alternatives))
 + [Homebrew Launcher (PicHaxx)](homebrew-launcher-(pichaxx))
 + [Homebrew Launcher (Soundhax)](homebrew-launcher-(soundhax))
-+ [Homebrew Launcher (Steelhax)](homebrew-launcher-(steelhax))
 + [Installing boot9strap (2xrsa)](installing-boot9strap-(2xrsa))
 + [Installing boot9strap (Browser)](installing-boot9strap-(browser))
 + [Installing boot9strap (Fredtool)](installing-boot9strap-(fredtool))
 + [Installing boot9strap (Frogtool)](installing-boot9strap-(frogtool))
 + [Installing boot9strap (Hardmod)](installing-boot9strap-(hardmod))
++ [Installing boot9strap (HBL-USM)](installing-boot9strap-(hbl-usm))
 + [Installing boot9strap (MSET)](installing-boot9strap-(mset))
 + [Installing boot9strap (ntrboot)](installing-boot9strap-(ntrboot))
 + [Installing boot9strap (SafeB9SInstaller)](installing-boot9strap-(safeb9sinstaller))
 + [Installing boot9strap (Soundhax)](installing-boot9strap-(soundhax))
 + [Installing boot9strap (USM)](installing-boot9strap-(usm))
-+ [Installing boot9strap (HBL-USM)](installing-boot9strap-(hbl-usm))
++ [Legacy Methods](legacy-methods)
 + [Move EmuNAND](move-emunand)
 + [ntrboot](ntrboot)
 + [Region Changing](region-changing)
 + [Seedminer](seedminer)
-+ [Legacy Seedminer Methods](legacy-methods)
 + [Troubleshooting](troubleshooting)
 + [Uninstall CFW](uninstall-cfw)
 + [Updating B9S](updating-b9s)