doc,assert: rename "mode" to "assertion mode"

Rename "strict mode" in the assert module to "strict assertion mode".
This is to avoid confusion with the more typical meaning of "strict
mode" in ECMAScript.

This necessitates a corresponding change of "legacy mode" to "legacy
assertion mode".

PR-URL: #31635
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

doc/api/assert.md

@@ -5,8 +5,8 @@
 > Stability: 2 - Stable
 
 The `assert` module provides a set of assertion functions for verifying
-invariants. The module provides a recommended [`strict` mode][] and a more
-lenient legacy mode.
+invariants. The module provides a recommended [strict assertion mode][]
+and a more lenient legacy assertion mode.
 
 ## Class: assert.AssertionError
 
@@ -68,26 +68,30 @@ try {
 }
 ```
 
-## Strict mode
+## Strict assertion mode
 <!-- YAML
 added: v9.9.0
 changes:
+  - version: REPLACEME
+    description: Changed "strict mode" to "strict assertion mode" and "legacy
+                 mode" to "legacy assertion mode" to avoid confusion with the
+                 more usual meaining of "strict mode".
   - version: v9.9.0
     pr-url: https://github.com/nodejs/node/pull/17615
-    description: Added error diffs to the strict mode
+    description: Added error diffs to the strict assertion mode.
   - version: v9.9.0
     pr-url: https://github.com/nodejs/node/pull/17002
-    description: Added strict mode to the assert module.
+    description: Added strict assertion mode to the assert module.
 -->
 
-In `strict` mode (not to be confused with `"use strict"`), `assert` functions
-use the comparison in the corresponding strict functions. For example,
-[`assert.deepEqual()`][] will behave like [`assert.deepStrictEqual()`][].
+In strict assertion mode, `assert` functions use the comparison in the
+corresponding strict functions. For example, [`assert.deepEqual()`][] will
+behave like [`assert.deepStrictEqual()`][].
 
-In `strict` mode, error messages for objects display a diff. In legacy mode,
-error messages for objects display the objects, often truncated.
+In strict assertion mode, error messages for objects display a diff. In legacy
+assertion mode, error messages for objects display the objects, often truncated.
 
-To use `strict` mode:
+To use strict assertion mode:
 
 ```js
 const assert = require('assert').strict;
@@ -121,22 +125,22 @@ This will also deactivate the colors in the REPL.
 For more on the color support in terminal environments, read
 the tty [getColorDepth()](tty.html#tty_writestream_getcolordepth_env) doc.
 
-## Legacy mode
+## Legacy assertion mode
 
-Legacy mode uses the [Abstract Equality Comparison][] in:
+Legacy assertion mode uses the [Abstract Equality Comparison][] in:
 
 * [`assert.deepEqual()`][]
 * [`assert.equal()`][]
 * [`assert.notDeepEqual()`][]
 * [`assert.notEqual()`][]
 
-To use legacy mode:
+To use legacy assertion mode:
 
 ```js
 const assert = require('assert');
 ```
 
-Whenever possible, use the [`strict` mode][] instead. Otherwise, the
+Whenever possible, use the [strict assertion mode][] instead. Otherwise, the
 [Abstract Equality Comparison][] may cause surprising results. This is
 especially true for [`assert.deepEqual()`][], where the comparison rules are
 lax:
@@ -185,11 +189,11 @@ changes:
 * `expected` {any}
 * `message` {string|Error}
 
-**Strict mode**
+**Strict assertion mode**
 
 An alias of [`assert.deepStrictEqual()`][].
 
-**Legacy mode**
+**Legacy assertion mode**
 
 > Stability: 0 - Deprecated: Use [`assert.deepStrictEqual()`][] instead.
 
@@ -596,11 +600,11 @@ added: v0.1.21
 * `expected` {any}
 * `message` {string|Error}
 
-**Strict mode**
+**Strict assertion mode**
 
 An alias of [`assert.strictEqual()`][].
 
-**Legacy mode**
+**Legacy assertion mode**
 
 > Stability: 0 - Deprecated: Use [`assert.strictEqual()`][] instead.
 
@@ -825,11 +829,11 @@ changes:
 * `expected` {any}
 * `message` {string|Error}
 
-**Strict mode**
+**Strict assertion mode**
 
 An alias of [`assert.notDeepStrictEqual()`][].
 
-**Legacy mode**
+**Legacy assertion mode**
 
 > Stability: 0 - Deprecated: Use [`assert.notDeepStrictEqual()`][] instead.
 
@@ -931,11 +935,11 @@ added: v0.1.21
 * `expected` {any}
 * `message` {string|Error}
 
-**Strict mode**
+**Strict assertion mode**
 
 An alias of [`assert.notStrictEqual()`][].
 
-**Legacy mode**
+**Legacy assertion mode**
 
 > Stability: 0 - Deprecated: Use [`assert.notStrictEqual()`][] instead.
 
@@ -1395,7 +1399,7 @@ argument.
 [`assert.ok()`]: #assert_assert_ok_value_message
 [`assert.strictEqual()`]: #assert_assert_strictequal_actual_expected_message
 [`assert.throws()`]: #assert_assert_throws_fn_error_message
-[`strict` mode]: #assert_strict_mode
+[strict assertion mode]: #assert_strict_assertion_mode
 [Abstract Equality Comparison]: https://tc39.github.io/ecma262/#sec-abstract-equality-comparison
 [Object wrappers]: https://developer.mozilla.org/en-US/docs/Glossary/Primitive#Primitive_wrapper_objects_in_JavaScript
 [Object.prototype.toString()]: https://tc39.github.io/ecma262/#sec-object.prototype.tostring