docs: Use \ instead of \\ in examples (#7286)

Instead of informing the bell character (hex 07), the example was using
an escaped \ followed by x07.

    $ echo \\x07
    \x07
    $ echo \x07

    $ echo \x07 | od -a
    0000000 bel  nl
    0000002
    $

* docs: Use \u instead of \\u

Instead of informing the Unicode character 慡, this example was using an
escaped \ followed by u6161.

    $ echo \\u6161
    \u6161
    $ echo \u6161
    慡

Before:

    $ string escape --style=var 'a1 b2'\\u6161 | string unescape --style=var
    a1 b2\u6161

Now:

    $ string escape --style=var 'a1 b2'\u6161 | string unescape --style=var
    a1 b2慡

doc_src/cmds/echo.rst

@@ -64,7 +64,7 @@ Example
    > echo 'Hello World'
    Hello World
 
-   > echo -e 'Top\\nBottom'
+   > echo -e 'Top\nBottom'
    Top
    Bottom
 

doc_src/cmds/printf.rst

@@ -77,7 +77,7 @@ Example
 
 ::
 
-    printf '%s\\t%s\\n' flounder fish
+    printf '%s\t%s\n' flounder fish
 
 Will print "flounder	fish" (separated with a tab character), followed by a newline character. This is useful for writing completions, as fish expects completion scripts to output the option followed by the description, separated with a tab character.
 

doc_src/cmds/string-escape.rst

@@ -37,11 +37,11 @@ Examples
 
 ::
 
-    >_ echo \\x07 | string escape
-    cg
+    >_ echo \x07 | string escape
+    \cg
 
-    >_ string escape --style=var 'a1 b2'\\u6161
-    a1_20b2__c_E6_85_A1
+    >_ string escape --style=var 'a1 b2'\u6161
+    a1_20_b2_E6_85_A1_
 
 
 .. END EXAMPLES

doc_src/cmds/string-match.rst

@@ -52,7 +52,7 @@ Match Glob Examples
     >_ string match -i 'a??B' Axxb
     Axxb
 
-    >_ echo 'ok?' | string match '*\\?'
+    >_ echo 'ok?' | string match '*\?'
     ok?
 
     # Note that only the second STRING will match here.

doc_src/cmds/string-replace.rst

@@ -53,13 +53,13 @@ Replace Regex Examples
 
 ::
 
-    >_ string replace -r -a '[^\\d.]+' ' ' '0 one two 3.14 four 5x'
+    >_ string replace -r -a '[^\d.]+' ' ' '0 one two 3.14 four 5x'
     0 3.14 5
 
-    >_ string replace -r '(\\w+)\\s+(\\w+)' '$2 $1 $$' 'left right'
+    >_ string replace -r '(\w+)\s+(\w+)' '$2 $1 $$' 'left right'
     right left $
 
-    >_ string replace -r '\\s*newline\\s*' '\\n' 'put a newline here'
+    >_ string replace -r '\s*newline\s*' '\n' 'put a newline here'
     put a
     here
 

doc_src/cmds/string-split.rst

@@ -66,9 +66,9 @@ NUL Delimited Examples
     42
 
     >_ # Sort a list of elements which may contain newlines
-    >_ set foo beta alpha\\ngamma
+    >_ set foo beta alpha\ngamma
     >_ set foo (string join0 $foo | sort -z | string split0)
     >_ string escape $foo[1]
-    alpha\\ngamma
+    alpha\ngamma
 
 .. END EXAMPLES

doc_src/cmds/string.rst

@@ -314,4 +314,4 @@ In contrast to ``grep``, ``string``\ s `match` defaults to glob-mode, while `rep
 
 Like ``sed``\ s `s/` command, ``string replace`` still prints strings that don't match. ``sed``\ s `-n` in combination with a `/p` modifier or command is like ``string replace -f``.
 
-``string split somedelimiter`` is a replacement for ``tr somedelimiter \\n``.
+``string split somedelimiter`` is a replacement for ``tr somedelimiter \n``.

doc_src/index.rst

@@ -1293,7 +1293,7 @@ Variable                                                   Meaning
 ``fish_color_comment``                                     comments like '# important'
 ``fish_color_selection``                                   selected text in vi visual mode
 ``fish_color_operator``                                    parameter expansion operators like '*' and '~'
-``fish_color_escape``                                      character escapes like '\\n' and '\\x70'
+``fish_color_escape``                                      character escapes like '\n' and '\x70'
 ``fish_color_autosuggestion``                              autosuggestions (the proposed rest of a command)
 ``fish_color_cwd``                                         the current working directory in the default prompt
 ``fish_color_user``                                        the username in the default prompt