Fix heading level of 'Try' section

It was agreed to be '## Try:' but there were many files where it was
'### Try:'. This has been corrected.

2020/burton/README.md

@@ -23,7 +23,7 @@ For more detailed information see [2020 burton in bugs.md](/bugs.md#2020-burton)
 ```
 
 
-### Try:
+## Try:
 
 ```sh
 ./try.sh

2020/carlini/README.md

@@ -23,7 +23,7 @@ For more detailed information see [2020 carlini in bugs.md](/bugs.md#2020-carlin
 ```
 
 
-### Try:
+## Try:
 
 ```sh
 ./try.sh

2020/endoh1/README.md

@@ -17,7 +17,7 @@ code](#alternate-code) below.
 ```
 
 
-### Try:
+## Try:
 
 ```sh
 # IMPORTANT for macOS: run under Terminal.app

2020/endoh2/README.md

@@ -12,7 +12,7 @@ make
 ```
 
 
-### Try:
+## Try:
 
 ```sh
 ./try.sh

2020/endoh3/README.md

@@ -15,7 +15,7 @@ code](#alternate-code) below.
 ```
 
 
-### Try:
+## Try:
 
 ```sh
 ./run_clock

2020/ferguson1/README.md

@@ -85,7 +85,7 @@ and non-zero).
 		(cannot - die if you try).
 
 
-### Try:
+## Try:
 
 ```sh
 make test

2020/ferguson2/README.md

@@ -47,7 +47,7 @@ at once. See [Alternate code](#alternate-code) below.
 are allowed.
 
 
-### Try:
+## Try:
 
 ```sh
 ./try.sh

2020/giles/README.md

@@ -31,7 +31,7 @@ frequency)](https://en.wikipedia.org/wiki/Dual-tone_multi-frequency_signaling)
 will be converted to the DTMF sound!
 
 
-### Try:
+## Try:
 
 ```sh
 ./try.sh

2020/kurdyukov1/README.md

@@ -20,7 +20,7 @@ echo text | ./prog
 ```
 
 
-### Try:
+## Try:
 
 ```sh
 ./try.sh

2020/kurdyukov2/README.md

@@ -12,7 +12,7 @@ make
 ```
 
 
-### Try:
+## Try:
 
 ```sh
 # Take a selfie

2020/kurdyukov3/README.md

@@ -15,7 +15,7 @@ code](#alternate-code) below.
 ```
 
 
-### Try:
+## Try:
 
 ```sh
 ./try.sh

2020/kurdyukov4/README.md

@@ -12,7 +12,7 @@ make
 ```
 
 
-### Try:
+## Try:
 
 When running this, ask yourself why it gets progressively slower when the
 context length decreases:

2020/otterness/README.md

@@ -23,7 +23,7 @@ For more detailed information see [2020 otterness in bugs.md](/bugs.md#2020-otte
 ```
 
 
-### Try:
+## Try:
 
 ```sh
 ./prog < cvikl.mid > output.mid

2020/tsoj/README.md

@@ -16,7 +16,7 @@ to those familiar with vi. See [Alternate code](#alternate-code) below.
 ```
 
 
-### Try:
+## Try:
 
 ```sh
 # Make your terminal as large as possible, possibly reduce your font size

2020/yang/README.md

@@ -12,7 +12,7 @@ make
 ```
 
 
-### Try:
+## Try:
 
 ```sh
 ./try.sh