Add docs for CLI and WHERE clause (#322)

* Fix #312

* Fix #311

src/content/docs/client-apis/cli.mdx

@@ -40,15 +40,14 @@ Opened the database under in-memory mode.
 Enter ":help" for usage hints.
 kuzu> 
 ```
-
 ## Shell commands
 
 Once you start the shell, you can issue Cypher queries as shown in the [get started](/get-started)
 section. List all available shell commands by running `./kuzu -h`.
 
 ```bash
-$ ./kuzu -h
-  ./kuzu [databasePath] {OPTIONS}
+$ kuzu -h
+  kuzu [databasePath] {OPTIONS}
 
     KuzuDB Shell
 
@@ -69,6 +68,20 @@ $ ./kuzu -h
       arguments to be treated as positional options
 ```
 
+:::caution[Note on memory usage]
+By default, Kùzu's CLI is launched with a maximum buffer pool size of 80% of the available memory.
+If you want to launch the Kùzu CLI with a different buffer pool size, you can do so by setting the
+`--defaultbpsize` or `-d` flag to the desired value in megabytes.
+:::
+
+
+To limit the buffer pool size to use just 4GB of memory, you can use the following command:
+
+```bash
+kuzu --defaultbpsize 4096
+```
+
+
 #### `:help`
 Show built-in command list within the Kùzu shell.
 

src/content/docs/cypher/query-clauses/where.md

@@ -21,13 +21,13 @@ RETURN *;
 ```
 Output:
 ```
----------------------------------------------
-| a                                         |
----------------------------------------------
-| (label:User, 0:1, {name:Karissa, age:40}) |
----------------------------------------------
-| (label:User, 0:2, {name:Zhang, age:50})   |
----------------------------------------------
+┌──────────────────────────────────────────────────┐
+│ a                                                │
+│ NODE                                             │
+├──────────────────────────────────────────────────┤
+│ {_ID: 0:1, _LABEL: User, name: Karissa, age: 40} │
+│ {_ID: 0:2, _LABEL: User, name: Zhang, age: 50}   │
+└──────────────────────────────────────────────────┘
 ```
 
 The boolean predicate specified above can be understood as it reads: Users "a" whose ages are
@@ -44,9 +44,33 @@ RETURN *;
 ```
 Output:
 ```
----------------------------------------------
-| a                                         |
----------------------------------------------
-| (label:User, 0:1, {name:Karissa, age:40}) |
----------------------------------------------
+┌──────────────────────────────────────────────────┐
+│ a                                                │
+│ NODE                                             │
+├──────────────────────────────────────────────────┤
+│ {_ID: 0:1, _LABEL: User, name: Karissa, age: 40} │
+└──────────────────────────────────────────────────┘
 ```
+
+## `WHERE` subquery on a relationship
+
+You can also specify a subquery that matches a relationship using the `WHERE` clause.
+
+```cypher
+MATCH (a:User)
+WHERE (a)-[r1:Follows]->(b:User {name: "Noura"})-[r2:LivesIn]->(c:City {name: "Guelph"})
+RETURN a;
+```
+```
+┌────────────────────────────────────────────────┐
+│ a                                              │
+│ NODE                                           │
+├────────────────────────────────────────────────┤
+│ {_ID: 0:2, _LABEL: User, name: Zhang, age: 50} │
+└────────────────────────────────────────────────┘
+```
+
+The above query matches users who follow "Noura" and lives in "Guelph". Note that you can only
+`RETURN` the nodes that are in the scope of the `MATCH` clause (the nodes and relationships that
+are in the `WHERE` clause are not returned).
+