Remove the mention of GCC_ARM, IAR as its not very relevant here.

theotherjimmy · SenRamakri · web-flow · commit 33ea6b35963b · 2019-03-13T17:22:09.000-05:00
Co-Authored-By: SenRamakri &lt;senthil.ramakrishnan@arm.com&gt;
diff --git a/docs/tools/tools_intro.md b/docs/tools/tools_intro.md
@@ -53,7 +53,7 @@ be able to compile with ARM Compiler 5 or you may see undefined behaviors. In ot
 
 ##### By creating a mbed_app.json to override `supported_toolchains`
 
-In this method, you can create or update your `mbed_app.json` with the following content. Note that you can still keep other entries such as `GCC_ARM` or `IAR` while overriding `supported_toolchains` as below.
+In this method, you can create or update your `mbed_app.json` with the following content. Override `supported_toolchains` as below.
 
 ```
 {

Original file line number	Diff line number	Diff line change
`@@ -53,7 +53,7 @@ be able to compile with ARM Compiler 5 or you may see undefined behaviors. In ot`
`53`	`53`
`54`	`54`	##### By creating a mbed_app.json to override `supported_toolchains`
`55`	`55`
`56`		-In this method, you can create or update your `mbed_app.json` with the following content. Note that you can still keep other entries such as `GCC_ARM` or `IAR` while overriding `supported_toolchains` as below.
	`56`	+In this method, you can create or update your `mbed_app.json` with the following content. Override `supported_toolchains` as below.
`57`	`57`
`58`	`58`	```
`59`	`59`	`{`