Update docs with deprecated region references (superfly#2273)

* add relative links and link machine placement guide

* update regions list

* update regions in code sample

* replace region in backup guide

Author: kcmartin

blueprints/going-to-production-with-healthcare-apps.html.md

@@ -72,19 +72,16 @@ If the default region is not where you want to host your application, run `fly p
 
 ```bash
 fly platform regions
-NAME                                          CODE  GATEWAY LAUNCH PLAN + ONLY  GPUS
-Amsterdam, Netherlands                        ams   ✓                           ✓
-Ashburn, Virginia (US)                        iad   ✓                           ✓
-Atlanta, Georgia (US)                         atl
-Bogotá, Colombia                              bog
-Boston, Massachusetts (US)                    bos
-Bucharest, Romania                            otp
-Chicago, Illinois (US)                        ord   ✓
-Dallas, Texas (US)                            dfw   ✓
-Denver, Colorado (US)                         den
-Ezeiza, Argentina                             eze
-Frankfurt, Germany                            fra   ✓       ✓
-Guadalajara, Mexico                           gdl
+NAME                        	CODE	GATEWAY	GPUS	CAPACITY	LAUNCH PLAN+
+
+North America
+Ashburn, Virginia (US)      	iad 	✓      	✓   	164
+Chicago, Illinois (US)      	ord 	✓      	      385
+Dallas, Texas (US)          	dfw 	✓      	      426
+Los Angeles, California (US)	lax 	✓      	      635
+San Jose, California (US)   	sjc 	✓      	✓     2399
+Secaucus, NJ (US)           	ewr                     233
+Toronto, Canada             	yyz 	✓      	      70
 # ... Lots more regions...
 ```
 

machines/guides-examples/machine-placement.html.md

@@ -80,7 +80,7 @@ This only helps if your app actually works when deployed across multiple regions
 
 <div class="callout">
 Want to see where your app might run? 
-Here's the [current list](/docs/reference/regions/): ams, arn, atl, bog, bom, bos, cdg, den, dfw, ewr, eze, fra, gdl, gig, gru, hkg, iad, jnb, lax, lhr, mad, mia, nrt, ord, otp, phx, qro, scl, sea, sin, sjc, syd, waw, yul, yyz.
+Here's the [current list](/docs/reference/regions/): ams, arn, bom, cdg, dfw, ewr, fra, gru, iad, jnb, lax, lhr, nrt, ord, sin, sjc, syd, yyz.
 </div>
 
 

postgres/managing/backup-and-restore.html.markerb

@@ -64,8 +64,8 @@ fly volumes list -a <postgres-app-name>
 ```
 ```output
 ID                   NAME    SIZE REGION ATTACHED VM CREATED AT
-vol_x915grn008vn70qy pg_data 10GB atl    b780ce3d    2 weeks ago
-vol_ke628r677pvwmnpy pg_data 10GB atl    359d0e24    2 weeks ago
+vol_x915grn008vn70qy pg_data 10GB sjc    b780ce3d    2 weeks ago
+vol_ke628r677pvwmnpy pg_data 10GB sjc    359d0e24    2 weeks ago
 ```
 
 The number of volumes varies depending on how many database replicas were elected when provisioning the database. One primary database and one replica yields 2 volumes.

reference/regions.html.markerb

@@ -39,10 +39,12 @@ You can host your apps in any of the following regions.
 
 ## Discovering your app's region
 
-View the list of Fly.io regions with [`fly platform regions`](https://fly.io/docs/flyctl/platform-regions).
+View the list of Fly.io regions with [`fly platform regions`](/docs/flyctl/platform-regions).
 
-You can see which regions your app is running in with [`fly status`](https://fly.io/docs/flyctl/status/).
+You can see which regions your app is running in with [`fly status`](/docs/flyctl/status/).
 
 [Fly Volumes](/docs/volumes/) and [Fly Machines](/docs/machines/) are tied to the region they're created in.
 
+Learn more about Machine placement and regional capacity in this [guide](/docs/machines/guides-examples/machine-placement/).
+
 When an application instance is started, the three-letter name for the region it's running in is stored in the Machine's `FLY_REGION`  environment variable. This, along with other [Runtime Environment](/docs/machines/runtime-environment/) information, is visible to your app running on that instance.