Merge pull request #443 from stan-dev/twiddle_to_tilde

Replace `twiddle` with `tilde`

Author: rok-cesnovar

src/stan-users-guide/using-stanc.Rmd

@@ -231,8 +231,8 @@ in more detail in following sections):
     constants are used as distribution arguments.
 -   *Control flow depends on a parameter.* Branching control flow (like if/else)
     depends on a parameter value .
--   *Parameter has multiple twiddles.* A parameter is on the left-hand side of
-    multiple twiddles.
+-   *Parameter has multiple tildes.* A parameter is on the left-hand side of
+    multiple tildes.
 -   *Parameter has zero or multiple priors.* A parameter has zero or more than
     one prior distribution.
 -   *Variable is used before assignment.* A variable is used before being
@@ -443,7 +443,7 @@ Warning at 'param-dep-cf-warn.stan', line 19, column 2 to line 21, column 3:
 ```
 
 
-### Parameters with multiple twiddles
+### Parameters with multiple tildes
 
 A warning is generated when a parameter is found on the left-hand side of more than one ~ statements (or an equivalent `target +=` conditional density statement). This pattern is not inherently an issue, but it is unusual and may indicate a mistake.
 
@@ -470,8 +470,8 @@ model {
 Pedantic mode produces the following warning.
 
 ```
-Warning at 'multi-twiddle.stan', line 9, column 2 to column 19:
-  The parameter a is on the left-hand side of more than one twiddle
+Warning at 'multi-tildes.stan', line 9, column 2 to column 19:
+  The parameter a is on the left-hand side of more than one tildes
   statement.
 ```