Change "can not" to "cannot" in many places

[slel]

Many code comments, docstrings or error messages
have "can not" where "cannot" would seem better.

This ticket is to fix that.

To find such occurrences, change to the Sage root folder and run:

$ git grep "can not" src

CC: @fchapoton @slel

Component: documentation

Keywords: typo

Author: Frédéric Chapoton

Branch/Commit: 344cfba

Reviewer: Samuel Lelièvre

Issue created by migration from https://trac.sagemath.org/ticket/30471

[slel]

comment:1

One might also search for (line ending with "can"
possibly followed by any number of whitespace characters)
followed by (line starting with "not" possibly preceded
by any number of whitespace characters).

I don't know how to do that.

[fchapoton]

Author: Frédéric Chapoton

[fchapoton]

comment:2

Voila déjà un bon gros début. Suffisant pour un premier ticket ?

---

New commits:

ee191a2	change "can not" to "cannot" in most pyx files
f434d7b	change "can not" to "cannot" in error messages

[fchapoton]

Branch: u/chapoton/30471

[fchapoton]

Commit: f434d7b

[mantepse]

comment:3

As far as I know, both writings may be correct, depending on circumstances. Supporting evidence: https://brians.wsu.edu/2016/05/31/cannot/

[slel]

comment:4

Agree with @mantepse's comment but still think it's worth changing here.

I'm rephrasing the ticket summary and description to not call this a typo.

Positive review from me if the bots are happy.

[slel]

Description changed:

--- 
+++ 
@@ -1,9 +1,11 @@
-Many code comments or docstrings have "can not" for "cannot".
+Many code comments, docstrings or error messages
+have "can not" where "cannot" would seem better.
 
-To find them, change to the Sage root folder and run:
+This ticket is to fix that.
+
+To find such occurrences, change to the Sage root folder and run:
 
 ```bash
 $ git grep "can not" src
 ```
 
-This ticket is to fix that.