As a new user of Rust, I would like to say that I find foo<', T> very very unfortunate. Try reading it without the monospace font: foo<’, T>. The symbols are dancing around on the baseline… is it a speck of dust? or is it an apostrophe? 
Also, the apostrophe followed by a comma almost looks like a ;.
This kind of syntax is anything but elegant and moves Rust more towards the line-noise camp of languages — I’m a Python guy, so lots of special characters and symbols are not “elegant” to my eyes I feel code should be optimized for readability since it’s normally read by many more people that the person who writes it.
Do I understand it correctly that the proposal simply allows the programmer to use ' instead of 'a when there is just one lifetime? If so, please just keep the more explicit syntax. Explicit is better than implicit, and all that, as they say in the Python world 
There is some precedense for using 'foo in programming languages – Lisp use that syntax for its atoms. It’s pretty readable even though apostorphes are normally attached to the end of a word. But a free floating apostrophe? Please don’t.