Keywords are parsed as functions in select statements

# Abstract
Qualified names like of the form `.` are sometimes parsed as functions, like in:

```sql
SELECT t.user FROM t;
```

# Current Behavior
This is done with `cargo run --example cli -- test.sql --generic`:

```sql
select t.user from t;
```

results in:

```text
[
Query(
Query {
with: None,
body: Select(
Select {
select_token: TokenWithSpan {
token: Word(
Word {
value: "select",
quote_style: None,
keyword: SELECT,
},
),
span: Span(Location(1,1)..Location(1,7)),
},
distinct: None,
top: None,
top_before_distinct: false,
projection: [
UnnamedExpr(
Function(
Function {
name: ObjectName(
[
Identifier(
Ident {
value: "t",
quote_style: None,
span: Span(Location(1,8)..Location(1,9)),
},
),
Identifier(
Ident {
value: "user",
quote_style: None,
span: Span(Location(1,10)..Location(1,14)),
},
),
],
),
uses_odbc_syntax: false,
parameters: None,
args: None,
filter: None,
null_treatment: None,
over: None,
within_group: [],
},
),
),
],
into: None,
from: [
TableWithJoins {
relation: Table {
name: ObjectName(
[
Identifier(
Ident {
value: "t",
quote_style: None,
span: Span(Location(1,20)..Location(1,21)),
},
),
],
),
alias: None,
args: None,
with_hints: [],
version: None,
with_ordinality: false,
partitions: [],
json_path: None,
sample: None,
index_hints: [],
},
joins: [],
},
],
lateral_views: [],
prewhere: None,
selection: None,
group_by: Expressions(
[],
[],
),
cluster_by: [],
distribute_by: [],
sort_by: [],
having: None,
named_window: [],
qualify: None,
window_before_qualify: false,
value_table_mode: None,
connect_by: None,
flavor: Standard,
},
),
order_by: None,
limit_clause: None,
fetch: None,
locks: [],
for_clause: None,
settings: None,
format_clause: None,
pipe_operators: [],
},
),
]
```

and `cargo run --example cli -- test.sql --postgres` is the same:

```text
[
Query(
Query {
with: None,
body: Select(
Select {
select_token: TokenWithSpan {
token: Word(
Word {
value: "select",
quote_style: None,
keyword: SELECT,
},
),
span: Span(Location(1,1)..Location(1,7)),
},
distinct: None,
top: None,
top_before_distinct: false,
projection: [
UnnamedExpr(
Function(
Function {
name: ObjectName(
[
Identifier(
Ident {
value: "t",
quote_style: None,
span: Span(Location(1,8)..Location(1,9)),
},
),
Identifier(
Ident {
value: "user",
quote_style: None,
span: Span(Location(1,10)..Location(1,14)),
},
),
],
),
uses_odbc_syntax: false,
parameters: None,
args: None,
filter: None,
null_treatment: None,
over: None,
within_group: [],
},
),
),
],
into: None,
from: [
TableWithJoins {
relation: Table {
name: ObjectName(
[
Identifier(
Ident {
value: "t",
quote_style: None,
span: Span(Location(1,20)..Location(1,21)),
},
),
],
),
alias: None,
args: None,
with_hints: [],
version: None,
with_ordinality: false,
partitions: [],
json_path: None,
sample: None,
index_hints: [],
},
joins: [],
},
],
lateral_views: [],
prewhere: None,
selection: None,
group_by: Expressions(
[],
[],
),
cluster_by: [],
distribute_by: [],
sort_by: [],
having: None,
named_window: [],
qualify: None,
window_before_qualify: false,
value_table_mode: None,
connect_by: None,
flavor: Standard,
},
),
order_by: None,
limit_clause: None,
fetch: None,
locks: [],
for_clause: None,
settings: None,
format_clause: None,
pipe_operators: [],
},
),
]
```

# Expected Behavior
I think this should parse similar to

```sql
select t.foo from t;
```

with `cargo run --example cli -- test.sql --generic`:

```text
[
Query(
Query {
with: None,
body: Select(
Select {
select_token: TokenWithSpan {
token: Word(
Word {
value: "select",
quote_style: None,
keyword: SELECT,
},
),
span: Span(Location(1,1)..Location(1,7)),
},
distinct: None,
top: None,
top_before_distinct: false,
projection: [
UnnamedExpr(
CompoundIdentifier(
[
Ident {
value: "t",
quote_style: None,
span: Span(Location(1,8)..Location(1,9)),
},
Ident {
value: "foo",
quote_style: None,
span: Span(Location(1,10)..Location(1,13)),
},
],
),
),
],
into: None,
from: [
TableWithJoins {
relation: Table {
name: ObjectName(
[
Identifier(
Ident {
value: "t",
quote_style: None,
span: Span(Location(1,19)..Location(1,20)),
},
),
],
),
alias: None,
args: None,
with_hints: [],
version: None,
with_ordinality: false,
partitions: [],
json_path: None,
sample: None,
index_hints: [],
},
joins: [],
},
],
lateral_views: [],
prewhere: None,
selection: None,
group_by: Expressions(
[],
[],
),
cluster_by: [],
distribute_by: [],
sort_by: [],
having: None,
named_window: [],
qualify: None,
window_before_qualify: false,
value_table_mode: None,
connect_by: None,
flavor: Standard,
},
),
order_by: None,
limit_clause: None,
fetch: None,
locks: [],
for_clause: None,
settings: None,
format_clause: None,
pipe_operators: [],
},
),
]
```

# Others
Also see PostgreSQL:

```text
psql (17.5 (Debian 17.5-1.pgdg120+1))
Type "help" for help.

postgres=# create table t(a int, "user" text);
CREATE TABLE
postgres=# insert into t values (1, 'foo');
INSERT 0 1
postgres=# select t.user from t;
user
------
foo
(1 row)
```

Interestingly, even the plain `user` works:

```text
postgres=# select user from t;
user
----------
postgres
(1 row)
```

# References
- a potentially valid case of treating `user` as a function: #1658
- downstream: https://github.com/apache/datafusion/issues/14141

Reproduce the issue with the mentioned cargo run --example cli command using test.sql and both --generic and --postgres. Trace the SQL expression parsing that classifies t.user as a Function instead of the CompoundIdentifier shown for t.foo, then add coverage for the failing query and verify both dialects produce the expected parse form.

Written by the indexing model from the issue text.