Simplify syntax (#2991)

tests/examples_arguments_syntax/bar_chart_with_labels.py

@@ -7,19 +7,12 @@
 import altair as alt
 from vega_datasets import data
 
-source = data.wheat()
 
-bars = alt.Chart(source).mark_bar().encode(
-    x='wheat:Q',
-    y="year:O"
-)
+source = data.wheat()
 
-text = bars.mark_text(
-    align='left',
-    baseline='middle',
-    dx=3  # Nudges text to right so it doesn't appear on top of the bar
-).encode(
-    text='wheat:Q'
+base = alt.Chart(source).encode(
+    x='wheat',
+    y="year:O",
+    text='wheat'
 )
-
-(bars + text).properties(height=900)
+base.mark_bar() + base.mark_text(align='left', dx=2)