Fix a few typos in the faq (#201)

* Fix a few typos in the faq
Added info about using ?=
Changed debugger example to use Z as unbound variable, A causes grammar issue making it harder to read

* Longer story about BREAKCHECK

* A few more tweaks

---------

Co-authored-by: Larry Masinter <lmm@acm.org>

Author: MattHeffron

content/en/project/faqs.md

@@ -13,41 +13,52 @@ In Medley, there are three main editors used commonly:
 * TTYIN (Type-in using keyboard)
 
 The original method for copy/paste is different from most modern systems:
-* click with ouse the destination
-* hold down the shift key, and, while holding, select the source (using left mouwse button to select a point, right button or repeated left button to extend the selection)
+* click with mouse the destination
+* hold down the shift key, and, while holding, select the source (using left mouse button to select a point, right button or repeated left button to extend the selection)
 * let up the shift key. The system will copy from the selected content and paste it in the destination.
 
 To do a cut/paste operation, hold down the control key as well as the shift key.
 
-Modern Medley (in the CLUPBOARD software) adds an interface with the host OS's Clipboard.  Typing meta-C does copy to clipboard, and meta-V will paste from the clipboard into the destination. The 'meta' key is the one labeled 'cmd' on a Macintosh and 'alt' on most windows keyboards.
+Modern Medley (in the CLIPBOARD software) adds an interface with the host OS's Clipboard.  Typing meta-C does copy to clipboard, and meta-V will paste from the clipboard into the destination. The 'meta' key is the one labeled 'cmd' on a Macintosh, and the left side 'Alt' key on most windows keyboards.
 
 ## How to ask for help about a specific function?
 
 There is a graphical browser of the Interlisp Reference Manual -- right click any area of the screen not in a window (i.e., the background) and select DInfo.
 
-The `MAN` command can be used:
+The `MAN` command can be used in an EXEC:
 ```
 MAN HELP
 ```
-In addition,  typein of a list structure a question mark followed by a 'enter' will look up in the symbol entered in the enclosing list:
+In addition, typein of a list structure followed by a question mark followed by an 'enter' will look up (using DInfo) the symbol entered in the enclosing list:
 ```
-(list ?
+(CONS ?
 ```
-Modern Medley extends this to look up Commonn Lisp functioins in the Common Lisp HyperSpec.
+Modern Medley extends this to look up Common Lisp functions in the Common Lisp HyperSpec. 
 
+Further, typein of a expression form followed by a question mark and equals sign followed by an 'enter' will look up the _closest_ function name (for any defined function) entered in the form and display that function's invocation form:
+```
+(SETQ FOO (LOAD ?=
+```
+shows
+```
+(LOAD FILE LDFLG PRINTFLG)
+```
 Interlisp EXEC commands are case and package insensitive, although the rest of the input line depends on the context.
 
 ## When to pop up a debugger or just report an error and unwind?
 
-The command `retry` will redo a typein but invoke the debugger.
+Interlisp uses a heuristic to decide when to simply print an error message and when to open a "break" window for the error; the decision is based on compute-time-since-last-user-input and stack depth. We've adjusted these parameters but modern machines are 1000 times faster, and the clock resolution is too coarse.
+
+The `retry` command is handy in this situation.
 
-For example typing (+ 1 A) will only show the error message:
-A is an unbound variable.
+For example typing `(+ 1 Z)` may only show the error message:  
+`Z is an unbound variable.`  
+without a break window opening. If you 
 ```
  RETRY
 ```
-  and a debugger window will pop up. let's give A a value while in the debugger:
+then a debugger window will pop up. Let's give Z a value while in the debugger:
 ```
-(SETQ A 9)
+(SETQ Z 9)
 ```
-now middle click in the debugger then choose Ok and it will continue the execution as if the fault never happened. It will return the value 10.
+now type `OK` and _enter_ (or middle click in the debugger then choose Ok). It will continue the execution as if the fault never happened. It will return the value 10.