some fixes to expression tutorial (#101558)

dev_docs/tutorials/expressions.mdx

@@ -10,10 +10,12 @@ tags: ['kibana', 'onboarding', 'dev', 'architecture']
 ## Expressions service
 
 Expression service exposes a registry of reusable functions primary used for fetching and transposing data and a registry of renderer functions that can render data into a DOM element.
-Adding functions is easy and so is reusing them. An expression is a chain of functions with provided arguments, which given a single input translates to a single output.
+Adding functions is easy and so is reusing them.
+ 
+An expression is a chain of functions with provided arguments, which given a single input translates to a single output.
 Each expression is representable by a human friendly string which a user can type.
 
-### creating expressions
+### Creating expressions
 
 Here is a very simple expression string:
 
@@ -23,7 +25,7 @@ essql 'select column1, column2 from myindex' | mapColumn name=column3 fn='{ colu
 
 It consists of 3 functions:
 
- - essql which runs given sql query against elasticsearch and returns the results
+ - `essql` which runs given sql query against elasticsearch and returns the results
  - `mapColumn`, which computes a new column from existing ones;
  - `table`, which prepares the data for rendering in a tabular format.
 
@@ -41,7 +43,7 @@ const expression = buildExpression([
 
 Note: Consumers need to be aware which plugin registers specific functions with expressions function registry and import correct type definitions from there.
 
-<DocCallOut title="Server Side Search">
+<DocCallOut>
   The `expressions` service is available on both server and client, with similar APIs.
 </DocCallOut>
 
@@ -54,7 +56,7 @@ const executionContract = expressions.execute(expression, input);
 const result = await executionContract.getData();
 ```
 
-<DocCallOut title="Server Side Search">
+<DocCallOut>
   Check the full spec of execute function [here](https://github.com/elastic/kibana/blob/master/docs/development/plugins/expressions/public/kibana-plugin-plugins-expressions-public.execution.md)
 </DocCallOut>
 
@@ -68,7 +70,7 @@ This is the easiest way to get expressions rendered inside your application.
 <ReactExpressionRenderer expression={expression} />
 ```
 
-<DocCallOut title="Server Side Search">
+<DocCallOut>
   Check the full spec of ReactExpressionRenderer component props [here](https://github.com/elastic/kibana/blob/master/docs/development/plugins/expressions/public/kibana-plugin-plugins-expressions-public.reactexpressionrendererprops.md)
 </DocCallOut>
 
@@ -80,7 +82,7 @@ If you are not using React, you can use the loader expression service provides t
 const handler = loader(domElement, expression, params);
 ```
 
-<DocCallOut title="Server Side Search">
+<DocCallOut>
   Check the full spec of expression loader params [here](https://github.com/elastic/kibana/blob/master/docs/development/plugins/expressions/public/kibana-plugin-plugins-expressions-public.iexpressionloaderparams.md)
 </DocCallOut>
 
@@ -103,7 +105,7 @@ const functionDefinition = {
 expressions.registerFunction(functionDefinition);
 ```
 
-<DocCallOut title="Server Side Search">
+<DocCallOut>
   Check the full interface of ExpressionFuntionDefinition [here](https://github.com/elastic/kibana/blob/master/docs/development/plugins/expressions/public/kibana-plugin-plugins-expressions-public.expressionfunctiondefinition.md)
 </DocCallOut>
 
@@ -125,6 +127,6 @@ const rendererDefinition = {
 expressions.registerRenderer(rendererDefinition);
 ```
 
-<DocCallOut title="Server Side Search">
+<DocCallOut>
   Check the full interface of ExpressionRendererDefinition [here](https://github.com/elastic/kibana/blob/master/docs/development/plugins/expressions/public/kibana-plugin-plugins-expressions-public.expressionrenderdefinition.md)
 </DocCallOut>