Fix issue 20554 - std.algorithm.searching.all 's static assert produc…

[jrfondren]

…es a garbled error message

Currently the static assert strips the first and last character from pred.stringof. Illustrative drepl session:

D> import std;
std
D> "hi".all!isWhite
static assert:  "`sWhit` isn't a unary predicate function for range.front"
/tmp/drepl.bcFRnD/_mod1.d(10):        instantiated from here: `all!string`

D> "hi".all!(c => c.isWhite)
static assert:  "`_lambda` isn't a unary predicate function for range.front"
/tmp/drepl.bcFRnD/_mod1.d(10):        instantiated from here: `all!string`

D> "hi".all!"a.isWhite"
static assert:  "`a.isWhite` isn't a unary predicate function for range.front"
/tmp/drepl.bcFRnD/_mod1.d(10):        instantiated from here: `all!string`

This PR fixes this in the direction of not stripping ever, which results in embedded doublequotes while not rendering all!X and all!"X" identically.

Drepl session with the patch:

D> import std;
std
D> "hi".all!isWhite
static assert:  "`isWhite` isn't a unary predicate function for range.front"
/tmp/drepl.rnH8WL/_mod1.d(10):        instantiated from here: `all!string`

D> "hi".all!(c => c.isWhite)
static assert:  "`__lambda2` isn't a unary predicate function for range.front"
/tmp/drepl.rnH8WL/_mod1.d(10):        instantiated from here: `all!string`

D> "hi".all!"a.isWhite"
static assert:  "`"a.isWhite"` isn't a unary predicate function for range.front"
/tmp/drepl.rnH8WL/_mod1.d(10):        instantiated from here: `all!string`

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Bugzilla references

Auto-close	Bugzilla	Severity	Description
✓	20554	trivial	std.algorithm.searching.all 's static assert produces a garbled error message

Testing this PR locally

If you don't have a local development environment setup, you can use Digger to test this PR:

dub run digger -- build "master + phobos#8246"