[README] Coarse sweep to use markup in READMEs.

This should improve online readability of the readme files.

examples/stm32/l1/stm32l-discovery/button-irq-printf/README.md

@@ -1,3 +1,5 @@
+# README
+
 * Prints to the screen when the button is pushed/released (irq driven)
   115200@8n1 console on PA2 (tx only)
 * uses basic timer 6 with overflows to generate a 1ms counter (not an ideal
@@ -11,25 +13,24 @@ is ~7.5mA when the green tick led is off, and about 10.5mA when it is on.
 
 example output:
 
-hi guys!
-TICK 0
-TICK 1
-TICK 2
-Pushed down!
-held: 443 ms
-Pushed down!
-TICK 3
-held: 217 ms
-Pushed down!
-held: 99 ms
-Pushed down!
-TICK 4
-held: 73 ms
-Pushed down!
-held: 60 ms
-TICK 5
-Pushed down!
-held: 98 ms
-Pushed down!
-
+    hi guys!
+    TICK 0
+    TICK 1
+    TICK 2
+    Pushed down!
+    held: 443 ms
+    Pushed down!
+    TICK 3
+    held: 217 ms
+    Pushed down!
+    held: 99 ms
+    Pushed down!
+    TICK 4
+    held: 73 ms
+    Pushed down!
+    held: 60 ms
+    TICK 5
+    Pushed down!
+    held: 98 ms
+    Pushed down!