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.

2019/adamovsky/README.md

@@ -23,7 +23,7 @@ For more detailed information see [2019 adamovsky in bugs.md](/bugs.md#2019-adam
 ```
 
 
-### Try:
+## Try:
 
 ```sh
 ./try.sh

2019/burton/README.md

@@ -25,7 +25,7 @@ For more detailed information see [2019 burton in bugs.md](/bugs.md#2019-burton)
 ```
 
 
-### Try:
+## Try:
 
 ```sh
 ./try.sh

2019/ciura/README.md

@@ -27,7 +27,7 @@ For more detailed information see [2019 ciura in bugs.md](/bugs.md#2019-ciura).
 ```
 
 
-### Try:
+## Try:
 
 ```sh
 ./try.sh

2019/diels-grabsch1/README.md

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

2019/diels-grabsch2/README.md

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

2019/dogon/README.md

@@ -23,7 +23,7 @@ For more detailed information see [2019 dogon in bugs.md](/bugs.md#2019-dogon).
 ```
 
 
-### Try:
+## Try:
 
 ```sh
 ./try.sh

2019/duble/README.md

@@ -26,7 +26,7 @@ For more detailed information see [2019 duble in bugs.md](/bugs.md#2019-duble).
 ```
 
 
-### Try:
+## Try:
 
 ```sh
 ./prog /tmp/drawing

2019/endoh/README.md

@@ -26,7 +26,7 @@ For more detailed information see [2019 endoh in bugs.md](/bugs.md#2019-endoh).
 ```
 
 
-### Try:
+## Try:
 
 If you have `gdb(1)` installed:
 

2019/giles/README.md

@@ -12,7 +12,7 @@ make
 ```
 
 
-### Try:
+## Try:
 
 ```sh
 play MonodyVocals.wav

2019/karns/README.md

@@ -34,7 +34,7 @@ reset
 after running the program to restore the terminal to its previous state.
 
 
-### Try:
+## Try:
 
 ```sh
 ./try.sh

2019/lynn/README.md

@@ -23,7 +23,7 @@ For more detailed information see [2019 lynn in bugs.md](/bugs.md#2019-lynn).
 ```
 
 
-### Try:
+## Try:
 
 ```sh
 ./try.sh

2019/mills/README.md

@@ -25,7 +25,7 @@ make cpclean
 ```
 
 
-### Try:
+## Try:
 
 ```sh
 ./try.sh

2019/poikola/README.md

@@ -46,7 +46,7 @@ make docs
 This will create the file `poikola.pdf` for your enjoyment.
 
 
-### Try:
+## Try:
 
 If you don't have a few days, try:
 

2019/yang/README.md

@@ -33,7 +33,7 @@ cat a b c d | ./prog
 ```
 
 
-### Try:
+## Try:
 
 ```sh
 ./try.sh