Update documentation

spring-shell-docs/modules/ROOT/pages/testing/index.adoc

@@ -4,15 +4,14 @@
 
 ifndef::snippets[:snippets: ../../../../src/test/java/org/springframework/shell/docs]
 
-Testing cli application is difficult due to various reasons:
+Testing CLI application is difficult due to various reasons:
 
 - There are differences between OS's.
-- Within OS there may be different shell implementations in use.
-- What goes into a shell and comes out from a shell my be totally
-  different what you see in shell itself due to control characters.
-- Shell may feel syncronous but most likely it is not meaning when
-  someting is written into it, you can't assume next update in
-  in it is not final.
+- Within the same OS there may be different shell implementations in use.
+- What goes into a shell and comes out from a shell may be totally
+  different from what you see in the shell itself due to invisible control characters.
+- The shell may feel synchronous but most likely it is not, meaning when
+  something is written into it, you can't assume next update in it is not final.
 
 NOTE: Testing support is currently under development and will be
       unstable for various parts.

spring-shell-docs/modules/ROOT/pages/testing/settings.adoc

@@ -3,11 +3,11 @@
 
 ifndef::snippets[:snippets: ../../../../src/test/java/org/springframework/shell/docs]
 
-Built in emulation uses terminal width 80 and height 24 on default.
-Changing dimensions is useful if output would span into multiple
-lines and you don't want to handle those cases in a tests.
+Built-in emulation uses terminal width 80 and height 24 by default.
+Changing dimensions is useful if the output would span multiple lines
+and you don't want to handle those cases in a tests.
 
-These can be changed using properties `spring.shell.test.terminal-width`
+These settings can be changed using properties `spring.shell.test.terminal-width`
 or `spring.shell.test.terminal-height`.
 
 [source, java, indent=0]