Update torproject.org links

wiki/src/doc/first_steps/welcome_screen/bridge_mode.mdwn

@@ -29,7 +29,7 @@ to know that you are using Tor.
 If you are in one of the situations described above
 you might want to use Tor bridges in Tails. Please also read
 The Tor Project's [dedicated page about
-bridges](https://www.torproject.org/docs/bridges) to get a general
+bridges](https://tb-manual.torproject.org/bridges/) to get a general
 idea about what bridges are.
 
 In order to use Tor through bridges, you must know the address of at
@@ -76,7 +76,7 @@ If using Tor is dangerous in your country
 =========================================
 
 The Tor Project's [documentation on
-bridges](https://www.torproject.org/docs/bridges) mainly focuses on
+bridges](https://tb-manual.torproject.org/bridges/) mainly focuses on
 censorship circumvention: when using Tor is blocked by
 censorship. If using Tor is dangerous or considered suspicious in your
 country, then there are some extra rules that you should follow in order
@@ -93,7 +93,7 @@ an adversary could do to identify Tor users.
 1. Always start Tails in *bridge mode*.
 
 2. Only use [*obfuscated
-   bridges*](https://www.torproject.org/docs/bridges#PluggableTransports)
+   bridges*](https://tb-manual.torproject.org/circumvention)
    since they are harder to identify than other bridges.
 
 3. The less publicly known the bridges are, the better.