antlr4: Implement error handling using the catch keyword

Author: hexaredecimal

src/main/java/org/piccode/antlr4/PiccodeScript.interp

@@ -40,13 +40,14 @@ MODULE=39
 DO=40
 USE=41
 RETURN_TOK=42
-NUMBER=43
-STRING=44
-DOT=45
-LINE_COMMENT=46
-BLOCK_COMMENT=47
-ID=48
-WS=49
+CATCH_TOK=43
+NUMBER=44
+STRING=45
+DOT=46
+LINE_COMMENT=47
+BLOCK_COMMENT=48
+ID=49
+WS=50
 '+'=1
 '-'=2
 '*'=3
@@ -89,4 +90,5 @@ WS=49
 'do'=40
 'use'=41
 'return'=42
-'.'=45
+'catch'=43
+'.'=46

src/main/java/org/piccode/antlr4/PiccodeScript.tokens

@@ -40,13 +40,14 @@ MODULE=39
 DO=40
 USE=41
 RETURN_TOK=42
-NUMBER=43
-STRING=44
-DOT=45
-LINE_COMMENT=46
-BLOCK_COMMENT=47
-ID=48
-WS=49
+CATCH_TOK=43
+NUMBER=44
+STRING=45
+DOT=46
+LINE_COMMENT=47
+BLOCK_COMMENT=48
+ID=49
+WS=50
 '+'=1
 '-'=2
 '*'=3
@@ -89,4 +90,5 @@ WS=49
 'do'=40
 'use'=41
 'return'=42
-'.'=45
+'catch'=43
+'.'=46