Partly revert wordy changes introduced in 9965

wiki/src/doc/first_steps/persistence.mdwn

 [[!meta title="Encrypted persistence"]]
 
-If you start from a Tails USB stick, you can create a
+If you start Tails from a USB stick, you can create a
 persistent volume in the free space left on the device by <span
 class="application">Tails Installer</span>. The files in the persistent
 volume are saved encrypted and remain available across separate working sessions.

wiki/src/support/known_issues.mdwn

@@ -70,7 +70,7 @@ This USB stick doesn't start Tails at all, the USB 2.0 workaround is not working
 Acer Travelmate 8573T-254G50M
 -----------------------------
 
-Booting from DVD works fine, but does not start from Tails USB sticks,
+Booting from DVD works fine, but does not start from USB sticks,
 created using Tails Installer.
 
 This problem might be corrected in Tails 1.1 and newer: please report
@@ -79,7 +79,7 @@ your test results back to us.
 Acer Aspire 5315-ICL50 and Acer ES-1-331
 ----------------------------------------
 
-Does not start on Tails USB sticks, created using Tails Installer.
+Does not start on USB sticks, created using Tails Installer.
 
 ASUS VivoBook X202E
 -------------------
@@ -99,7 +99,7 @@ device installed using Tails Installer.
 Dell Inc. Latitude E6430 and E6230
 ----------------------------------
 
-Does not start on Tails USB sticks, created using Tails Installer.
+Does not start on USB sticks, created using Tails Installer.
 
 With BIOS versions A03 06/03/2012 (and A09, A11, and A12)
 
@@ -114,7 +114,7 @@ your test results back to us.
 Dell XPS L702X/03RG89, Samsung RV520, Samsung Series 7 Chronos
 --------------------------------------------------------------
 
-Does not start on Tails USB sticks, created using Tails Installer.
+Does not start on USB sticks, created using Tails Installer.
 
 We were reported that the legacy BIOS shipped on these systems doesn't
 know how to deal with the GPT partition scheme installed by Tails
@@ -143,7 +143,7 @@ newer versions: please report your test results back to us.
 Fujitsu Siemens Amilo A 1667G
 -----------------------------
 
-Does not start on Tails USB sticks, created using Tails Installer.
+Does not start on USB sticks, created using Tails Installer.
 
 HP Compaq dc5750 Microtower
 ---------------------------
@@ -180,7 +180,7 @@ Goes back continuously to Boot Loader Menu on Tails installed on DVD.
 Clevo W258CU, ThinkPad X121e, T420i, T410, T520, W520, T530, E325, and E530
 ---------------------------------------------------------------------------
 
-These machines do not start on TailsUSB sticks, created using Tails USB
+These machines do not start on USB sticks, created using Tails
 Installer, due to a firmware limitation.
 
 A workaround for some of these machines is to use the [[manual