fix: remove grammar for create/alter compiled SQL scalar function (#2738)

* fix: remove grammar for create/alter compiled SQL scalar function

remove grammar for create/alter compiled SQL scalar function.
It seems COBOL exec sql block doesn't support this statement.
In general, COBOL doesn't seems to support PL SQL.

Signed-off-by: amanprashant <[email protected]>

* revert: revert changes for db2sql_data_types rule

Signed-off-by: amanprashant <[email protected]>

* chore: clean up PL SQL related statements from the Cobol Db2 grammar

Signed-off-by: amanprashant <[email protected]>

* chore: clean up unsupported procedures grammar from the Cobol Db2 grammar

Signed-off-by: amanprashant <[email protected]>

* chore: remove commented codes

Signed-off-by: amanprashant <[email protected]>

* revert: revert gammar changes for alter functions that can be compiled

Signed-off-by: amanprashant <[email protected]>

* revert: revert grammar changes for alter procedures that can be compiled

Signed-off-by: amanprashant <[email protected]>

* fix: clean up as per PR comments

Signed-off-by: amanprashant <[email protected]>

---------

Signed-off-by: amanprashant <[email protected]>

Author: ap891843

server/engine/src/main/antlr4/org/eclipse/lsp/cobol/implicitDialects/sql/Db2SqlExecLexer.g4

@@ -325,6 +325,7 @@ FILLER: F I L L E R;
 FINAL : F I N A L;
 FIRST : F I R S T;
 FIRST_VALUE: F I R S T UNDERSCORECHAR V A L U E;
+FIXEDLENGTH: F I X E D LENGTH;
 FLOAT : F L O A T;
 FOLLOWING : F O L L O W I N G;
 FOR : F O R;
@@ -364,6 +365,7 @@ HISTORY : H I S T O R Y;
 HOLD : H O L D;
 HOUR : H O U R;
 HOURS : H O U R S;
+HUFFMAN: H U F F M A N;
 ID : I D;
 IDENTITY : I D E N T I T Y;
 IF : I F;
@@ -667,6 +669,7 @@ SOURCE : S O U R C E;
 SPACE : S P A C E;
 SPECIAL : S P E C I A L;
 SPECIFIC : S P E C I F I C;
+SQL: S Q L;
 SQLIMS: S Q L I M S;
 SQLADM : S Q L A D M;
 SQLCA : S Q L C A;