fix: edits to SQL lessons

Co-authored-by: Srihari Thyagarajan <57552973+Haleshot@users.noreply.github.com>

- Update sql/02_filter.py
- Update sql/03_aggregate_group.py
- Update sql/05_join.py
- Update sql/06_keys.py
- Update sql/06_keys.py
- Update sql/06_keys.py

sql/02_filter.py

@@ -278,7 +278,7 @@ def _():
     mo.md(r"""
     ## Check Understanding
 
-    ![concept map](/public/02_concepts.svg)
+    ![concept map](./public/02_concepts.svg)
     """)
     return
 

sql/03_aggregate_group.py

@@ -372,7 +372,7 @@ def _():
     mo.md(r"""
     ## Check Understanding
 
-    ![concept map](/public/03_concepts.svg)
+    ![concept map](./public/03_concepts.svg)
     """)
     return
 

sql/05_join.py

@@ -273,7 +273,7 @@ def _():
     mo.md(r"""
     ## Check Understanding
 
-    ![concept map](/public/05_concepts.svg)
+    ![concept map](./public/05_concepts.svg)
     """)
     return
 

sql/06_keys.py

@@ -38,7 +38,7 @@ def _():
 
     The previous tutorial explained how to combine information from two tables using `inner join` and `left join`. This tutorial will explain how we can tell when it makes sense to do this, and introduce our first complex database. To start, let's look at a diagram showing the four tables in the `survey` database.
 
-    ![survey tables](/public/survey_tables.svg)
+    ![survey tables](./public/survey_tables.svg)
     """)
     return
 
@@ -281,7 +281,7 @@ def _():
 
 @app.cell
 def _():
-    mo.image(src="survey_tables.svg", alt="table diagram of survey database")
+    mo.image(src="./public/survey_tables.svg", alt="table diagram of survey database")
     return
 
 
@@ -437,7 +437,7 @@ def _():
     mo.md(r"""
     ## Check Understanding
 
-    ![concept map](/public/06_concepts.svg)
+    ![concept map](./public/06_concepts.svg)
     """)
     return