Refactor SQLParser to correctly classify COUNT and CURRENT_DATE as FUNCTION_NAME tokens

Author: xterao

src/test/testData/sql/parser/SQLParser.txt

@@ -32,7 +32,7 @@ SQL File(0,1310)
   PsiWhiteSpace('\n       ')(217,225)
   PsiElement(SqlTokenType.,)(',')(225,226)
   PsiWhiteSpace(' ')(226,227)
-  PsiElement(SqlTokenType.WORD)('COUNT')(227,232)
+  PsiElement(SqlTokenType.FUNCTION_NAME)('COUNT')(227,232)
   PsiElement(SqlTokenType.()('(')(232,233)
   PsiElement(SqlTokenType.WORD)('pe')(233,235)
   PsiElement(SqlTokenType..)('.')(235,236)
@@ -292,7 +292,7 @@ SQL File(0,1310)
   PsiWhiteSpace(' ')(878,879)
   PsiElement(SqlTokenType.<=)('<=')(879,881)
   PsiWhiteSpace(' ')(881,882)
-  PsiElement(SqlTokenType.WORD)('CURRENT_DATE')(882,894)
+  PsiElement(SqlTokenType.FUNCTION_NAME)('CURRENT_DATE')(882,894)
   PsiWhiteSpace('\n   ')(894,898)
   PsiElement(SqlTokenType.KEYWORD)('AND')(898,901)
   PsiWhiteSpace(' ')(901,902)
@@ -302,7 +302,7 @@ SQL File(0,1310)
   PsiWhiteSpace(' ')(913,914)
   PsiElement(SqlTokenType.>=)('>=')(914,916)
   PsiWhiteSpace(' ')(916,917)
-  PsiElement(SqlTokenType.WORD)('CURRENT_DATE')(917,929)
+  PsiElement(SqlTokenType.FUNCTION_NAME)('CURRENT_DATE')(917,929)
   PsiWhiteSpace('\n   ')(929,933)
   SqlBlockCommentImpl(BLOCK_COMMENT)(933,941)
     PsiElement(SqlTokenType./*)('/*')(933,935)