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.

2000/anderson/README.md

@@ -12,7 +12,7 @@ echo something | ./anderson
 ```
 
 
-### Try:
+## Try:
 
 ```sh
 ./try.sh

2000/bmeyer/README.md

@@ -12,7 +12,7 @@ make
 ```
 
 
-### Try:
+## Try:
 
 In a video window (white text on black background):
 

2000/briddlebane/README.md

@@ -12,7 +12,7 @@ make
 ```
 
 
-### Try:
+## Try:
 
 For some fun every time you log in try running this from your `.bashrc` or
 equivalent file!

2000/dhyang/README.md

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

2000/dlowe/README.md

@@ -32,7 +32,7 @@ For more detailed information see [2000 dlowe in bugs.md](/bugs.md#2000-dlowe).
 ```
 
 
-### Try:
+## Try:
 
 ```sh
 echo "13 14 15 16 17 + - * / p" | ./dlowe

2000/jarijyrki/README.md

@@ -16,7 +16,7 @@ You will need X11 header files and libraries installed to build this program.
 You will need a system capable of displaying the results of X Window programs.
 
 
-### Try:
+## Try:
 
 ```sh
 ./jarijyrki < finance.sheet > myedits.info

2000/natori/README.md

@@ -16,7 +16,7 @@ version](#alternate-code) below.
 ```
 
 
-### Try:
+## Try:
 
 ```sh
 ./try.sh

2000/primenum/README.md

@@ -26,7 +26,7 @@ echo n | ./primenum n
 NOTE: `n` is an integer.
 
 
-### Try:
+## Try:
 
 ```sh
 ./try.sh

2000/rince/README.md

@@ -33,7 +33,7 @@ That's not a bug, that's a feature.
 ```
 
 
-### Try:
+## Try:
 
 ```sh
 ./try.sh

2000/schneiderwent/README.md

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

2000/thadgavin/README.md

@@ -23,7 +23,7 @@ looked like back in 2000 (with a configurable speed). See the
 You can press 'q' at any time to exit.
 
 
-### Try:
+## Try:
 
 If you have SDL1 installed:
 

2000/tomx/README.md

@@ -15,7 +15,7 @@ There is an alternate version that compiles [mkentry.c](mkentry.c). See
 ```
 
 
-### Try:
+## Try:
 
 ```sh
 ./try.sh